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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * ring buffer based function tracer
4 *
5 * Copyright (C) 2007-2012 Steven Rostedt <srostedt@redhat.com>
6 * Copyright (C) 2008 Ingo Molnar <mingo@redhat.com>
7 *
8 * Originally taken from the RT patch by:
9 * Arnaldo Carvalho de Melo <acme@redhat.com>
10 *
11 * Based on code from the latency_tracer, that is:
12 * Copyright (C) 2004-2006 Ingo Molnar
13 * Copyright (C) 2004 Nadia Yvette Chambers
14 */
15#include <linux/ring_buffer.h>
16#include <generated/utsrelease.h>
17#include <linux/stacktrace.h>
18#include <linux/writeback.h>
19#include <linux/kallsyms.h>
20#include <linux/security.h>
21#include <linux/seq_file.h>
22#include <linux/irqflags.h>
23#include <linux/debugfs.h>
24#include <linux/tracefs.h>
25#include <linux/pagemap.h>
26#include <linux/hardirq.h>
27#include <linux/linkage.h>
28#include <linux/uaccess.h>
29#include <linux/vmalloc.h>
30#include <linux/ftrace.h>
31#include <linux/module.h>
32#include <linux/percpu.h>
33#include <linux/splice.h>
34#include <linux/kdebug.h>
35#include <linux/string.h>
36#include <linux/mount.h>
37#include <linux/rwsem.h>
38#include <linux/slab.h>
39#include <linux/ctype.h>
40#include <linux/init.h>
41#include <linux/panic_notifier.h>
42#include <linux/kmemleak.h>
43#include <linux/poll.h>
44#include <linux/nmi.h>
45#include <linux/fs.h>
46#include <linux/trace.h>
47#include <linux/sched/clock.h>
48#include <linux/sched/rt.h>
49#include <linux/fsnotify.h>
50#include <linux/irq_work.h>
51#include <linux/workqueue.h>
52
53#include <asm/setup.h> /* COMMAND_LINE_SIZE */
54
55#include "trace.h"
56#include "trace_output.h"
57
58#ifdef CONFIG_FTRACE_STARTUP_TEST
59/*
60 * We need to change this state when a selftest is running.
61 * A selftest will lurk into the ring-buffer to count the
62 * entries inserted during the selftest although some concurrent
63 * insertions into the ring-buffer such as trace_printk could occurred
64 * at the same time, giving false positive or negative results.
65 */
66static bool __read_mostly tracing_selftest_running;
67
68/*
69 * If boot-time tracing including tracers/events via kernel cmdline
70 * is running, we do not want to run SELFTEST.
71 */
72bool __read_mostly tracing_selftest_disabled;
73
74void __init disable_tracing_selftest(const char *reason)
75{
76 if (!tracing_selftest_disabled) {
77 tracing_selftest_disabled = true;
78 pr_info("Ftrace startup test is disabled due to %s\n", reason);
79 }
80}
81#else
82#define tracing_selftest_running 0
83#define tracing_selftest_disabled 0
84#endif
85
86/* Pipe tracepoints to printk */
87static struct trace_iterator *tracepoint_print_iter;
88int tracepoint_printk;
89static bool tracepoint_printk_stop_on_boot __initdata;
90static DEFINE_STATIC_KEY_FALSE(tracepoint_printk_key);
91
92/* For tracers that don't implement custom flags */
93static struct tracer_opt dummy_tracer_opt[] = {
94 { }
95};
96
97static int
98dummy_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
99{
100 return 0;
101}
102
103/*
104 * To prevent the comm cache from being overwritten when no
105 * tracing is active, only save the comm when a trace event
106 * occurred.
107 */
108static DEFINE_PER_CPU(bool, trace_taskinfo_save);
109
110/*
111 * Kill all tracing for good (never come back).
112 * It is initialized to 1 but will turn to zero if the initialization
113 * of the tracer is successful. But that is the only place that sets
114 * this back to zero.
115 */
116static int tracing_disabled = 1;
117
118cpumask_var_t __read_mostly tracing_buffer_mask;
119
120/*
121 * ftrace_dump_on_oops - variable to dump ftrace buffer on oops
122 *
123 * If there is an oops (or kernel panic) and the ftrace_dump_on_oops
124 * is set, then ftrace_dump is called. This will output the contents
125 * of the ftrace buffers to the console. This is very useful for
126 * capturing traces that lead to crashes and outputing it to a
127 * serial console.
128 *
129 * It is default off, but you can enable it with either specifying
130 * "ftrace_dump_on_oops" in the kernel command line, or setting
131 * /proc/sys/kernel/ftrace_dump_on_oops
132 * Set 1 if you want to dump buffers of all CPUs
133 * Set 2 if you want to dump the buffer of the CPU that triggered oops
134 */
135
136enum ftrace_dump_mode ftrace_dump_on_oops;
137
138/* When set, tracing will stop when a WARN*() is hit */
139int __disable_trace_on_warning;
140
141#ifdef CONFIG_TRACE_EVAL_MAP_FILE
142/* Map of enums to their values, for "eval_map" file */
143struct trace_eval_map_head {
144 struct module *mod;
145 unsigned long length;
146};
147
148union trace_eval_map_item;
149
150struct trace_eval_map_tail {
151 /*
152 * "end" is first and points to NULL as it must be different
153 * than "mod" or "eval_string"
154 */
155 union trace_eval_map_item *next;
156 const char *end; /* points to NULL */
157};
158
159static DEFINE_MUTEX(trace_eval_mutex);
160
161/*
162 * The trace_eval_maps are saved in an array with two extra elements,
163 * one at the beginning, and one at the end. The beginning item contains
164 * the count of the saved maps (head.length), and the module they
165 * belong to if not built in (head.mod). The ending item contains a
166 * pointer to the next array of saved eval_map items.
167 */
168union trace_eval_map_item {
169 struct trace_eval_map map;
170 struct trace_eval_map_head head;
171 struct trace_eval_map_tail tail;
172};
173
174static union trace_eval_map_item *trace_eval_maps;
175#endif /* CONFIG_TRACE_EVAL_MAP_FILE */
176
177int tracing_set_tracer(struct trace_array *tr, const char *buf);
178static void ftrace_trace_userstack(struct trace_array *tr,
179 struct trace_buffer *buffer,
180 unsigned int trace_ctx);
181
182#define MAX_TRACER_SIZE 100
183static char bootup_tracer_buf[MAX_TRACER_SIZE] __initdata;
184static char *default_bootup_tracer;
185
186static bool allocate_snapshot;
187static bool snapshot_at_boot;
188
189static char boot_instance_info[COMMAND_LINE_SIZE] __initdata;
190static int boot_instance_index;
191
192static char boot_snapshot_info[COMMAND_LINE_SIZE] __initdata;
193static int boot_snapshot_index;
194
195static int __init set_cmdline_ftrace(char *str)
196{
197 strscpy(bootup_tracer_buf, str, MAX_TRACER_SIZE);
198 default_bootup_tracer = bootup_tracer_buf;
199 /* We are using ftrace early, expand it */
200 trace_set_ring_buffer_expanded(NULL);
201 return 1;
202}
203__setup("ftrace=", set_cmdline_ftrace);
204
205static int __init set_ftrace_dump_on_oops(char *str)
206{
207 if (*str++ != '=' || !*str || !strcmp("1", str)) {
208 ftrace_dump_on_oops = DUMP_ALL;
209 return 1;
210 }
211
212 if (!strcmp("orig_cpu", str) || !strcmp("2", str)) {
213 ftrace_dump_on_oops = DUMP_ORIG;
214 return 1;
215 }
216
217 return 0;
218}
219__setup("ftrace_dump_on_oops", set_ftrace_dump_on_oops);
220
221static int __init stop_trace_on_warning(char *str)
222{
223 if ((strcmp(str, "=0") != 0 && strcmp(str, "=off") != 0))
224 __disable_trace_on_warning = 1;
225 return 1;
226}
227__setup("traceoff_on_warning", stop_trace_on_warning);
228
229static int __init boot_alloc_snapshot(char *str)
230{
231 char *slot = boot_snapshot_info + boot_snapshot_index;
232 int left = sizeof(boot_snapshot_info) - boot_snapshot_index;
233 int ret;
234
235 if (str[0] == '=') {
236 str++;
237 if (strlen(str) >= left)
238 return -1;
239
240 ret = snprintf(slot, left, "%s\t", str);
241 boot_snapshot_index += ret;
242 } else {
243 allocate_snapshot = true;
244 /* We also need the main ring buffer expanded */
245 trace_set_ring_buffer_expanded(NULL);
246 }
247 return 1;
248}
249__setup("alloc_snapshot", boot_alloc_snapshot);
250
251
252static int __init boot_snapshot(char *str)
253{
254 snapshot_at_boot = true;
255 boot_alloc_snapshot(str);
256 return 1;
257}
258__setup("ftrace_boot_snapshot", boot_snapshot);
259
260
261static int __init boot_instance(char *str)
262{
263 char *slot = boot_instance_info + boot_instance_index;
264 int left = sizeof(boot_instance_info) - boot_instance_index;
265 int ret;
266
267 if (strlen(str) >= left)
268 return -1;
269
270 ret = snprintf(slot, left, "%s\t", str);
271 boot_instance_index += ret;
272
273 return 1;
274}
275__setup("trace_instance=", boot_instance);
276
277
278static char trace_boot_options_buf[MAX_TRACER_SIZE] __initdata;
279
280static int __init set_trace_boot_options(char *str)
281{
282 strscpy(trace_boot_options_buf, str, MAX_TRACER_SIZE);
283 return 1;
284}
285__setup("trace_options=", set_trace_boot_options);
286
287static char trace_boot_clock_buf[MAX_TRACER_SIZE] __initdata;
288static char *trace_boot_clock __initdata;
289
290static int __init set_trace_boot_clock(char *str)
291{
292 strscpy(trace_boot_clock_buf, str, MAX_TRACER_SIZE);
293 trace_boot_clock = trace_boot_clock_buf;
294 return 1;
295}
296__setup("trace_clock=", set_trace_boot_clock);
297
298static int __init set_tracepoint_printk(char *str)
299{
300 /* Ignore the "tp_printk_stop_on_boot" param */
301 if (*str == '_')
302 return 0;
303
304 if ((strcmp(str, "=0") != 0 && strcmp(str, "=off") != 0))
305 tracepoint_printk = 1;
306 return 1;
307}
308__setup("tp_printk", set_tracepoint_printk);
309
310static int __init set_tracepoint_printk_stop(char *str)
311{
312 tracepoint_printk_stop_on_boot = true;
313 return 1;
314}
315__setup("tp_printk_stop_on_boot", set_tracepoint_printk_stop);
316
317unsigned long long ns2usecs(u64 nsec)
318{
319 nsec += 500;
320 do_div(nsec, 1000);
321 return nsec;
322}
323
324static void
325trace_process_export(struct trace_export *export,
326 struct ring_buffer_event *event, int flag)
327{
328 struct trace_entry *entry;
329 unsigned int size = 0;
330
331 if (export->flags & flag) {
332 entry = ring_buffer_event_data(event);
333 size = ring_buffer_event_length(event);
334 export->write(export, entry, size);
335 }
336}
337
338static DEFINE_MUTEX(ftrace_export_lock);
339
340static struct trace_export __rcu *ftrace_exports_list __read_mostly;
341
342static DEFINE_STATIC_KEY_FALSE(trace_function_exports_enabled);
343static DEFINE_STATIC_KEY_FALSE(trace_event_exports_enabled);
344static DEFINE_STATIC_KEY_FALSE(trace_marker_exports_enabled);
345
346static inline void ftrace_exports_enable(struct trace_export *export)
347{
348 if (export->flags & TRACE_EXPORT_FUNCTION)
349 static_branch_inc(&trace_function_exports_enabled);
350
351 if (export->flags & TRACE_EXPORT_EVENT)
352 static_branch_inc(&trace_event_exports_enabled);
353
354 if (export->flags & TRACE_EXPORT_MARKER)
355 static_branch_inc(&trace_marker_exports_enabled);
356}
357
358static inline void ftrace_exports_disable(struct trace_export *export)
359{
360 if (export->flags & TRACE_EXPORT_FUNCTION)
361 static_branch_dec(&trace_function_exports_enabled);
362
363 if (export->flags & TRACE_EXPORT_EVENT)
364 static_branch_dec(&trace_event_exports_enabled);
365
366 if (export->flags & TRACE_EXPORT_MARKER)
367 static_branch_dec(&trace_marker_exports_enabled);
368}
369
370static void ftrace_exports(struct ring_buffer_event *event, int flag)
371{
372 struct trace_export *export;
373
374 preempt_disable_notrace();
375
376 export = rcu_dereference_raw_check(ftrace_exports_list);
377 while (export) {
378 trace_process_export(export, event, flag);
379 export = rcu_dereference_raw_check(export->next);
380 }
381
382 preempt_enable_notrace();
383}
384
385static inline void
386add_trace_export(struct trace_export **list, struct trace_export *export)
387{
388 rcu_assign_pointer(export->next, *list);
389 /*
390 * We are entering export into the list but another
391 * CPU might be walking that list. We need to make sure
392 * the export->next pointer is valid before another CPU sees
393 * the export pointer included into the list.
394 */
395 rcu_assign_pointer(*list, export);
396}
397
398static inline int
399rm_trace_export(struct trace_export **list, struct trace_export *export)
400{
401 struct trace_export **p;
402
403 for (p = list; *p != NULL; p = &(*p)->next)
404 if (*p == export)
405 break;
406
407 if (*p != export)
408 return -1;
409
410 rcu_assign_pointer(*p, (*p)->next);
411
412 return 0;
413}
414
415static inline void
416add_ftrace_export(struct trace_export **list, struct trace_export *export)
417{
418 ftrace_exports_enable(export);
419
420 add_trace_export(list, export);
421}
422
423static inline int
424rm_ftrace_export(struct trace_export **list, struct trace_export *export)
425{
426 int ret;
427
428 ret = rm_trace_export(list, export);
429 ftrace_exports_disable(export);
430
431 return ret;
432}
433
434int register_ftrace_export(struct trace_export *export)
435{
436 if (WARN_ON_ONCE(!export->write))
437 return -1;
438
439 mutex_lock(&ftrace_export_lock);
440
441 add_ftrace_export(&ftrace_exports_list, export);
442
443 mutex_unlock(&ftrace_export_lock);
444
445 return 0;
446}
447EXPORT_SYMBOL_GPL(register_ftrace_export);
448
449int unregister_ftrace_export(struct trace_export *export)
450{
451 int ret;
452
453 mutex_lock(&ftrace_export_lock);
454
455 ret = rm_ftrace_export(&ftrace_exports_list, export);
456
457 mutex_unlock(&ftrace_export_lock);
458
459 return ret;
460}
461EXPORT_SYMBOL_GPL(unregister_ftrace_export);
462
463/* trace_flags holds trace_options default values */
464#define TRACE_DEFAULT_FLAGS \
465 (FUNCTION_DEFAULT_FLAGS | \
466 TRACE_ITER_PRINT_PARENT | TRACE_ITER_PRINTK | \
467 TRACE_ITER_ANNOTATE | TRACE_ITER_CONTEXT_INFO | \
468 TRACE_ITER_RECORD_CMD | TRACE_ITER_OVERWRITE | \
469 TRACE_ITER_IRQ_INFO | TRACE_ITER_MARKERS | \
470 TRACE_ITER_HASH_PTR)
471
472/* trace_options that are only supported by global_trace */
473#define TOP_LEVEL_TRACE_FLAGS (TRACE_ITER_PRINTK | \
474 TRACE_ITER_PRINTK_MSGONLY | TRACE_ITER_RECORD_CMD)
475
476/* trace_flags that are default zero for instances */
477#define ZEROED_TRACE_FLAGS \
478 (TRACE_ITER_EVENT_FORK | TRACE_ITER_FUNC_FORK)
479
480/*
481 * The global_trace is the descriptor that holds the top-level tracing
482 * buffers for the live tracing.
483 */
484static struct trace_array global_trace = {
485 .trace_flags = TRACE_DEFAULT_FLAGS,
486};
487
488void trace_set_ring_buffer_expanded(struct trace_array *tr)
489{
490 if (!tr)
491 tr = &global_trace;
492 tr->ring_buffer_expanded = true;
493}
494
495LIST_HEAD(ftrace_trace_arrays);
496
497int trace_array_get(struct trace_array *this_tr)
498{
499 struct trace_array *tr;
500 int ret = -ENODEV;
501
502 mutex_lock(&trace_types_lock);
503 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
504 if (tr == this_tr) {
505 tr->ref++;
506 ret = 0;
507 break;
508 }
509 }
510 mutex_unlock(&trace_types_lock);
511
512 return ret;
513}
514
515static void __trace_array_put(struct trace_array *this_tr)
516{
517 WARN_ON(!this_tr->ref);
518 this_tr->ref--;
519}
520
521/**
522 * trace_array_put - Decrement the reference counter for this trace array.
523 * @this_tr : pointer to the trace array
524 *
525 * NOTE: Use this when we no longer need the trace array returned by
526 * trace_array_get_by_name(). This ensures the trace array can be later
527 * destroyed.
528 *
529 */
530void trace_array_put(struct trace_array *this_tr)
531{
532 if (!this_tr)
533 return;
534
535 mutex_lock(&trace_types_lock);
536 __trace_array_put(this_tr);
537 mutex_unlock(&trace_types_lock);
538}
539EXPORT_SYMBOL_GPL(trace_array_put);
540
541int tracing_check_open_get_tr(struct trace_array *tr)
542{
543 int ret;
544
545 ret = security_locked_down(LOCKDOWN_TRACEFS);
546 if (ret)
547 return ret;
548
549 if (tracing_disabled)
550 return -ENODEV;
551
552 if (tr && trace_array_get(tr) < 0)
553 return -ENODEV;
554
555 return 0;
556}
557
558int call_filter_check_discard(struct trace_event_call *call, void *rec,
559 struct trace_buffer *buffer,
560 struct ring_buffer_event *event)
561{
562 if (unlikely(call->flags & TRACE_EVENT_FL_FILTERED) &&
563 !filter_match_preds(call->filter, rec)) {
564 __trace_event_discard_commit(buffer, event);
565 return 1;
566 }
567
568 return 0;
569}
570
571/**
572 * trace_find_filtered_pid - check if a pid exists in a filtered_pid list
573 * @filtered_pids: The list of pids to check
574 * @search_pid: The PID to find in @filtered_pids
575 *
576 * Returns true if @search_pid is found in @filtered_pids, and false otherwise.
577 */
578bool
579trace_find_filtered_pid(struct trace_pid_list *filtered_pids, pid_t search_pid)
580{
581 return trace_pid_list_is_set(filtered_pids, search_pid);
582}
583
584/**
585 * trace_ignore_this_task - should a task be ignored for tracing
586 * @filtered_pids: The list of pids to check
587 * @filtered_no_pids: The list of pids not to be traced
588 * @task: The task that should be ignored if not filtered
589 *
590 * Checks if @task should be traced or not from @filtered_pids.
591 * Returns true if @task should *NOT* be traced.
592 * Returns false if @task should be traced.
593 */
594bool
595trace_ignore_this_task(struct trace_pid_list *filtered_pids,
596 struct trace_pid_list *filtered_no_pids,
597 struct task_struct *task)
598{
599 /*
600 * If filtered_no_pids is not empty, and the task's pid is listed
601 * in filtered_no_pids, then return true.
602 * Otherwise, if filtered_pids is empty, that means we can
603 * trace all tasks. If it has content, then only trace pids
604 * within filtered_pids.
605 */
606
607 return (filtered_pids &&
608 !trace_find_filtered_pid(filtered_pids, task->pid)) ||
609 (filtered_no_pids &&
610 trace_find_filtered_pid(filtered_no_pids, task->pid));
611}
612
613/**
614 * trace_filter_add_remove_task - Add or remove a task from a pid_list
615 * @pid_list: The list to modify
616 * @self: The current task for fork or NULL for exit
617 * @task: The task to add or remove
618 *
619 * If adding a task, if @self is defined, the task is only added if @self
620 * is also included in @pid_list. This happens on fork and tasks should
621 * only be added when the parent is listed. If @self is NULL, then the
622 * @task pid will be removed from the list, which would happen on exit
623 * of a task.
624 */
625void trace_filter_add_remove_task(struct trace_pid_list *pid_list,
626 struct task_struct *self,
627 struct task_struct *task)
628{
629 if (!pid_list)
630 return;
631
632 /* For forks, we only add if the forking task is listed */
633 if (self) {
634 if (!trace_find_filtered_pid(pid_list, self->pid))
635 return;
636 }
637
638 /* "self" is set for forks, and NULL for exits */
639 if (self)
640 trace_pid_list_set(pid_list, task->pid);
641 else
642 trace_pid_list_clear(pid_list, task->pid);
643}
644
645/**
646 * trace_pid_next - Used for seq_file to get to the next pid of a pid_list
647 * @pid_list: The pid list to show
648 * @v: The last pid that was shown (+1 the actual pid to let zero be displayed)
649 * @pos: The position of the file
650 *
651 * This is used by the seq_file "next" operation to iterate the pids
652 * listed in a trace_pid_list structure.
653 *
654 * Returns the pid+1 as we want to display pid of zero, but NULL would
655 * stop the iteration.
656 */
657void *trace_pid_next(struct trace_pid_list *pid_list, void *v, loff_t *pos)
658{
659 long pid = (unsigned long)v;
660 unsigned int next;
661
662 (*pos)++;
663
664 /* pid already is +1 of the actual previous bit */
665 if (trace_pid_list_next(pid_list, pid, &next) < 0)
666 return NULL;
667
668 pid = next;
669
670 /* Return pid + 1 to allow zero to be represented */
671 return (void *)(pid + 1);
672}
673
674/**
675 * trace_pid_start - Used for seq_file to start reading pid lists
676 * @pid_list: The pid list to show
677 * @pos: The position of the file
678 *
679 * This is used by seq_file "start" operation to start the iteration
680 * of listing pids.
681 *
682 * Returns the pid+1 as we want to display pid of zero, but NULL would
683 * stop the iteration.
684 */
685void *trace_pid_start(struct trace_pid_list *pid_list, loff_t *pos)
686{
687 unsigned long pid;
688 unsigned int first;
689 loff_t l = 0;
690
691 if (trace_pid_list_first(pid_list, &first) < 0)
692 return NULL;
693
694 pid = first;
695
696 /* Return pid + 1 so that zero can be the exit value */
697 for (pid++; pid && l < *pos;
698 pid = (unsigned long)trace_pid_next(pid_list, (void *)pid, &l))
699 ;
700 return (void *)pid;
701}
702
703/**
704 * trace_pid_show - show the current pid in seq_file processing
705 * @m: The seq_file structure to write into
706 * @v: A void pointer of the pid (+1) value to display
707 *
708 * Can be directly used by seq_file operations to display the current
709 * pid value.
710 */
711int trace_pid_show(struct seq_file *m, void *v)
712{
713 unsigned long pid = (unsigned long)v - 1;
714
715 seq_printf(m, "%lu\n", pid);
716 return 0;
717}
718
719/* 128 should be much more than enough */
720#define PID_BUF_SIZE 127
721
722int trace_pid_write(struct trace_pid_list *filtered_pids,
723 struct trace_pid_list **new_pid_list,
724 const char __user *ubuf, size_t cnt)
725{
726 struct trace_pid_list *pid_list;
727 struct trace_parser parser;
728 unsigned long val;
729 int nr_pids = 0;
730 ssize_t read = 0;
731 ssize_t ret;
732 loff_t pos;
733 pid_t pid;
734
735 if (trace_parser_get_init(&parser, PID_BUF_SIZE + 1))
736 return -ENOMEM;
737
738 /*
739 * Always recreate a new array. The write is an all or nothing
740 * operation. Always create a new array when adding new pids by
741 * the user. If the operation fails, then the current list is
742 * not modified.
743 */
744 pid_list = trace_pid_list_alloc();
745 if (!pid_list) {
746 trace_parser_put(&parser);
747 return -ENOMEM;
748 }
749
750 if (filtered_pids) {
751 /* copy the current bits to the new max */
752 ret = trace_pid_list_first(filtered_pids, &pid);
753 while (!ret) {
754 trace_pid_list_set(pid_list, pid);
755 ret = trace_pid_list_next(filtered_pids, pid + 1, &pid);
756 nr_pids++;
757 }
758 }
759
760 ret = 0;
761 while (cnt > 0) {
762
763 pos = 0;
764
765 ret = trace_get_user(&parser, ubuf, cnt, &pos);
766 if (ret < 0)
767 break;
768
769 read += ret;
770 ubuf += ret;
771 cnt -= ret;
772
773 if (!trace_parser_loaded(&parser))
774 break;
775
776 ret = -EINVAL;
777 if (kstrtoul(parser.buffer, 0, &val))
778 break;
779
780 pid = (pid_t)val;
781
782 if (trace_pid_list_set(pid_list, pid) < 0) {
783 ret = -1;
784 break;
785 }
786 nr_pids++;
787
788 trace_parser_clear(&parser);
789 ret = 0;
790 }
791 trace_parser_put(&parser);
792
793 if (ret < 0) {
794 trace_pid_list_free(pid_list);
795 return ret;
796 }
797
798 if (!nr_pids) {
799 /* Cleared the list of pids */
800 trace_pid_list_free(pid_list);
801 pid_list = NULL;
802 }
803
804 *new_pid_list = pid_list;
805
806 return read;
807}
808
809static u64 buffer_ftrace_now(struct array_buffer *buf, int cpu)
810{
811 u64 ts;
812
813 /* Early boot up does not have a buffer yet */
814 if (!buf->buffer)
815 return trace_clock_local();
816
817 ts = ring_buffer_time_stamp(buf->buffer);
818 ring_buffer_normalize_time_stamp(buf->buffer, cpu, &ts);
819
820 return ts;
821}
822
823u64 ftrace_now(int cpu)
824{
825 return buffer_ftrace_now(&global_trace.array_buffer, cpu);
826}
827
828/**
829 * tracing_is_enabled - Show if global_trace has been enabled
830 *
831 * Shows if the global trace has been enabled or not. It uses the
832 * mirror flag "buffer_disabled" to be used in fast paths such as for
833 * the irqsoff tracer. But it may be inaccurate due to races. If you
834 * need to know the accurate state, use tracing_is_on() which is a little
835 * slower, but accurate.
836 */
837int tracing_is_enabled(void)
838{
839 /*
840 * For quick access (irqsoff uses this in fast path), just
841 * return the mirror variable of the state of the ring buffer.
842 * It's a little racy, but we don't really care.
843 */
844 smp_rmb();
845 return !global_trace.buffer_disabled;
846}
847
848/*
849 * trace_buf_size is the size in bytes that is allocated
850 * for a buffer. Note, the number of bytes is always rounded
851 * to page size.
852 *
853 * This number is purposely set to a low number of 16384.
854 * If the dump on oops happens, it will be much appreciated
855 * to not have to wait for all that output. Anyway this can be
856 * boot time and run time configurable.
857 */
858#define TRACE_BUF_SIZE_DEFAULT 1441792UL /* 16384 * 88 (sizeof(entry)) */
859
860static unsigned long trace_buf_size = TRACE_BUF_SIZE_DEFAULT;
861
862/* trace_types holds a link list of available tracers. */
863static struct tracer *trace_types __read_mostly;
864
865/*
866 * trace_types_lock is used to protect the trace_types list.
867 */
868DEFINE_MUTEX(trace_types_lock);
869
870/*
871 * serialize the access of the ring buffer
872 *
873 * ring buffer serializes readers, but it is low level protection.
874 * The validity of the events (which returns by ring_buffer_peek() ..etc)
875 * are not protected by ring buffer.
876 *
877 * The content of events may become garbage if we allow other process consumes
878 * these events concurrently:
879 * A) the page of the consumed events may become a normal page
880 * (not reader page) in ring buffer, and this page will be rewritten
881 * by events producer.
882 * B) The page of the consumed events may become a page for splice_read,
883 * and this page will be returned to system.
884 *
885 * These primitives allow multi process access to different cpu ring buffer
886 * concurrently.
887 *
888 * These primitives don't distinguish read-only and read-consume access.
889 * Multi read-only access are also serialized.
890 */
891
892#ifdef CONFIG_SMP
893static DECLARE_RWSEM(all_cpu_access_lock);
894static DEFINE_PER_CPU(struct mutex, cpu_access_lock);
895
896static inline void trace_access_lock(int cpu)
897{
898 if (cpu == RING_BUFFER_ALL_CPUS) {
899 /* gain it for accessing the whole ring buffer. */
900 down_write(&all_cpu_access_lock);
901 } else {
902 /* gain it for accessing a cpu ring buffer. */
903
904 /* Firstly block other trace_access_lock(RING_BUFFER_ALL_CPUS). */
905 down_read(&all_cpu_access_lock);
906
907 /* Secondly block other access to this @cpu ring buffer. */
908 mutex_lock(&per_cpu(cpu_access_lock, cpu));
909 }
910}
911
912static inline void trace_access_unlock(int cpu)
913{
914 if (cpu == RING_BUFFER_ALL_CPUS) {
915 up_write(&all_cpu_access_lock);
916 } else {
917 mutex_unlock(&per_cpu(cpu_access_lock, cpu));
918 up_read(&all_cpu_access_lock);
919 }
920}
921
922static inline void trace_access_lock_init(void)
923{
924 int cpu;
925
926 for_each_possible_cpu(cpu)
927 mutex_init(&per_cpu(cpu_access_lock, cpu));
928}
929
930#else
931
932static DEFINE_MUTEX(access_lock);
933
934static inline void trace_access_lock(int cpu)
935{
936 (void)cpu;
937 mutex_lock(&access_lock);
938}
939
940static inline void trace_access_unlock(int cpu)
941{
942 (void)cpu;
943 mutex_unlock(&access_lock);
944}
945
946static inline void trace_access_lock_init(void)
947{
948}
949
950#endif
951
952#ifdef CONFIG_STACKTRACE
953static void __ftrace_trace_stack(struct trace_buffer *buffer,
954 unsigned int trace_ctx,
955 int skip, struct pt_regs *regs);
956static inline void ftrace_trace_stack(struct trace_array *tr,
957 struct trace_buffer *buffer,
958 unsigned int trace_ctx,
959 int skip, struct pt_regs *regs);
960
961#else
962static inline void __ftrace_trace_stack(struct trace_buffer *buffer,
963 unsigned int trace_ctx,
964 int skip, struct pt_regs *regs)
965{
966}
967static inline void ftrace_trace_stack(struct trace_array *tr,
968 struct trace_buffer *buffer,
969 unsigned long trace_ctx,
970 int skip, struct pt_regs *regs)
971{
972}
973
974#endif
975
976static __always_inline void
977trace_event_setup(struct ring_buffer_event *event,
978 int type, unsigned int trace_ctx)
979{
980 struct trace_entry *ent = ring_buffer_event_data(event);
981
982 tracing_generic_entry_update(ent, type, trace_ctx);
983}
984
985static __always_inline struct ring_buffer_event *
986__trace_buffer_lock_reserve(struct trace_buffer *buffer,
987 int type,
988 unsigned long len,
989 unsigned int trace_ctx)
990{
991 struct ring_buffer_event *event;
992
993 event = ring_buffer_lock_reserve(buffer, len);
994 if (event != NULL)
995 trace_event_setup(event, type, trace_ctx);
996
997 return event;
998}
999
1000void tracer_tracing_on(struct trace_array *tr)
1001{
1002 if (tr->array_buffer.buffer)
1003 ring_buffer_record_on(tr->array_buffer.buffer);
1004 /*
1005 * This flag is looked at when buffers haven't been allocated
1006 * yet, or by some tracers (like irqsoff), that just want to
1007 * know if the ring buffer has been disabled, but it can handle
1008 * races of where it gets disabled but we still do a record.
1009 * As the check is in the fast path of the tracers, it is more
1010 * important to be fast than accurate.
1011 */
1012 tr->buffer_disabled = 0;
1013 /* Make the flag seen by readers */
1014 smp_wmb();
1015}
1016
1017/**
1018 * tracing_on - enable tracing buffers
1019 *
1020 * This function enables tracing buffers that may have been
1021 * disabled with tracing_off.
1022 */
1023void tracing_on(void)
1024{
1025 tracer_tracing_on(&global_trace);
1026}
1027EXPORT_SYMBOL_GPL(tracing_on);
1028
1029
1030static __always_inline void
1031__buffer_unlock_commit(struct trace_buffer *buffer, struct ring_buffer_event *event)
1032{
1033 __this_cpu_write(trace_taskinfo_save, true);
1034
1035 /* If this is the temp buffer, we need to commit fully */
1036 if (this_cpu_read(trace_buffered_event) == event) {
1037 /* Length is in event->array[0] */
1038 ring_buffer_write(buffer, event->array[0], &event->array[1]);
1039 /* Release the temp buffer */
1040 this_cpu_dec(trace_buffered_event_cnt);
1041 /* ring_buffer_unlock_commit() enables preemption */
1042 preempt_enable_notrace();
1043 } else
1044 ring_buffer_unlock_commit(buffer);
1045}
1046
1047int __trace_array_puts(struct trace_array *tr, unsigned long ip,
1048 const char *str, int size)
1049{
1050 struct ring_buffer_event *event;
1051 struct trace_buffer *buffer;
1052 struct print_entry *entry;
1053 unsigned int trace_ctx;
1054 int alloc;
1055
1056 if (!(tr->trace_flags & TRACE_ITER_PRINTK))
1057 return 0;
1058
1059 if (unlikely(tracing_selftest_running && tr == &global_trace))
1060 return 0;
1061
1062 if (unlikely(tracing_disabled))
1063 return 0;
1064
1065 alloc = sizeof(*entry) + size + 2; /* possible \n added */
1066
1067 trace_ctx = tracing_gen_ctx();
1068 buffer = tr->array_buffer.buffer;
1069 ring_buffer_nest_start(buffer);
1070 event = __trace_buffer_lock_reserve(buffer, TRACE_PRINT, alloc,
1071 trace_ctx);
1072 if (!event) {
1073 size = 0;
1074 goto out;
1075 }
1076
1077 entry = ring_buffer_event_data(event);
1078 entry->ip = ip;
1079
1080 memcpy(&entry->buf, str, size);
1081
1082 /* Add a newline if necessary */
1083 if (entry->buf[size - 1] != '\n') {
1084 entry->buf[size] = '\n';
1085 entry->buf[size + 1] = '\0';
1086 } else
1087 entry->buf[size] = '\0';
1088
1089 __buffer_unlock_commit(buffer, event);
1090 ftrace_trace_stack(tr, buffer, trace_ctx, 4, NULL);
1091 out:
1092 ring_buffer_nest_end(buffer);
1093 return size;
1094}
1095EXPORT_SYMBOL_GPL(__trace_array_puts);
1096
1097/**
1098 * __trace_puts - write a constant string into the trace buffer.
1099 * @ip: The address of the caller
1100 * @str: The constant string to write
1101 * @size: The size of the string.
1102 */
1103int __trace_puts(unsigned long ip, const char *str, int size)
1104{
1105 return __trace_array_puts(&global_trace, ip, str, size);
1106}
1107EXPORT_SYMBOL_GPL(__trace_puts);
1108
1109/**
1110 * __trace_bputs - write the pointer to a constant string into trace buffer
1111 * @ip: The address of the caller
1112 * @str: The constant string to write to the buffer to
1113 */
1114int __trace_bputs(unsigned long ip, const char *str)
1115{
1116 struct ring_buffer_event *event;
1117 struct trace_buffer *buffer;
1118 struct bputs_entry *entry;
1119 unsigned int trace_ctx;
1120 int size = sizeof(struct bputs_entry);
1121 int ret = 0;
1122
1123 if (!(global_trace.trace_flags & TRACE_ITER_PRINTK))
1124 return 0;
1125
1126 if (unlikely(tracing_selftest_running || tracing_disabled))
1127 return 0;
1128
1129 trace_ctx = tracing_gen_ctx();
1130 buffer = global_trace.array_buffer.buffer;
1131
1132 ring_buffer_nest_start(buffer);
1133 event = __trace_buffer_lock_reserve(buffer, TRACE_BPUTS, size,
1134 trace_ctx);
1135 if (!event)
1136 goto out;
1137
1138 entry = ring_buffer_event_data(event);
1139 entry->ip = ip;
1140 entry->str = str;
1141
1142 __buffer_unlock_commit(buffer, event);
1143 ftrace_trace_stack(&global_trace, buffer, trace_ctx, 4, NULL);
1144
1145 ret = 1;
1146 out:
1147 ring_buffer_nest_end(buffer);
1148 return ret;
1149}
1150EXPORT_SYMBOL_GPL(__trace_bputs);
1151
1152#ifdef CONFIG_TRACER_SNAPSHOT
1153static void tracing_snapshot_instance_cond(struct trace_array *tr,
1154 void *cond_data)
1155{
1156 struct tracer *tracer = tr->current_trace;
1157 unsigned long flags;
1158
1159 if (in_nmi()) {
1160 trace_array_puts(tr, "*** SNAPSHOT CALLED FROM NMI CONTEXT ***\n");
1161 trace_array_puts(tr, "*** snapshot is being ignored ***\n");
1162 return;
1163 }
1164
1165 if (!tr->allocated_snapshot) {
1166 trace_array_puts(tr, "*** SNAPSHOT NOT ALLOCATED ***\n");
1167 trace_array_puts(tr, "*** stopping trace here! ***\n");
1168 tracer_tracing_off(tr);
1169 return;
1170 }
1171
1172 /* Note, snapshot can not be used when the tracer uses it */
1173 if (tracer->use_max_tr) {
1174 trace_array_puts(tr, "*** LATENCY TRACER ACTIVE ***\n");
1175 trace_array_puts(tr, "*** Can not use snapshot (sorry) ***\n");
1176 return;
1177 }
1178
1179 local_irq_save(flags);
1180 update_max_tr(tr, current, smp_processor_id(), cond_data);
1181 local_irq_restore(flags);
1182}
1183
1184void tracing_snapshot_instance(struct trace_array *tr)
1185{
1186 tracing_snapshot_instance_cond(tr, NULL);
1187}
1188
1189/**
1190 * tracing_snapshot - take a snapshot of the current buffer.
1191 *
1192 * This causes a swap between the snapshot buffer and the current live
1193 * tracing buffer. You can use this to take snapshots of the live
1194 * trace when some condition is triggered, but continue to trace.
1195 *
1196 * Note, make sure to allocate the snapshot with either
1197 * a tracing_snapshot_alloc(), or by doing it manually
1198 * with: echo 1 > /sys/kernel/tracing/snapshot
1199 *
1200 * If the snapshot buffer is not allocated, it will stop tracing.
1201 * Basically making a permanent snapshot.
1202 */
1203void tracing_snapshot(void)
1204{
1205 struct trace_array *tr = &global_trace;
1206
1207 tracing_snapshot_instance(tr);
1208}
1209EXPORT_SYMBOL_GPL(tracing_snapshot);
1210
1211/**
1212 * tracing_snapshot_cond - conditionally take a snapshot of the current buffer.
1213 * @tr: The tracing instance to snapshot
1214 * @cond_data: The data to be tested conditionally, and possibly saved
1215 *
1216 * This is the same as tracing_snapshot() except that the snapshot is
1217 * conditional - the snapshot will only happen if the
1218 * cond_snapshot.update() implementation receiving the cond_data
1219 * returns true, which means that the trace array's cond_snapshot
1220 * update() operation used the cond_data to determine whether the
1221 * snapshot should be taken, and if it was, presumably saved it along
1222 * with the snapshot.
1223 */
1224void tracing_snapshot_cond(struct trace_array *tr, void *cond_data)
1225{
1226 tracing_snapshot_instance_cond(tr, cond_data);
1227}
1228EXPORT_SYMBOL_GPL(tracing_snapshot_cond);
1229
1230/**
1231 * tracing_cond_snapshot_data - get the user data associated with a snapshot
1232 * @tr: The tracing instance
1233 *
1234 * When the user enables a conditional snapshot using
1235 * tracing_snapshot_cond_enable(), the user-defined cond_data is saved
1236 * with the snapshot. This accessor is used to retrieve it.
1237 *
1238 * Should not be called from cond_snapshot.update(), since it takes
1239 * the tr->max_lock lock, which the code calling
1240 * cond_snapshot.update() has already done.
1241 *
1242 * Returns the cond_data associated with the trace array's snapshot.
1243 */
1244void *tracing_cond_snapshot_data(struct trace_array *tr)
1245{
1246 void *cond_data = NULL;
1247
1248 local_irq_disable();
1249 arch_spin_lock(&tr->max_lock);
1250
1251 if (tr->cond_snapshot)
1252 cond_data = tr->cond_snapshot->cond_data;
1253
1254 arch_spin_unlock(&tr->max_lock);
1255 local_irq_enable();
1256
1257 return cond_data;
1258}
1259EXPORT_SYMBOL_GPL(tracing_cond_snapshot_data);
1260
1261static int resize_buffer_duplicate_size(struct array_buffer *trace_buf,
1262 struct array_buffer *size_buf, int cpu_id);
1263static void set_buffer_entries(struct array_buffer *buf, unsigned long val);
1264
1265int tracing_alloc_snapshot_instance(struct trace_array *tr)
1266{
1267 int order;
1268 int ret;
1269
1270 if (!tr->allocated_snapshot) {
1271
1272 /* Make the snapshot buffer have the same order as main buffer */
1273 order = ring_buffer_subbuf_order_get(tr->array_buffer.buffer);
1274 ret = ring_buffer_subbuf_order_set(tr->max_buffer.buffer, order);
1275 if (ret < 0)
1276 return ret;
1277
1278 /* allocate spare buffer */
1279 ret = resize_buffer_duplicate_size(&tr->max_buffer,
1280 &tr->array_buffer, RING_BUFFER_ALL_CPUS);
1281 if (ret < 0)
1282 return ret;
1283
1284 tr->allocated_snapshot = true;
1285 }
1286
1287 return 0;
1288}
1289
1290static void free_snapshot(struct trace_array *tr)
1291{
1292 /*
1293 * We don't free the ring buffer. instead, resize it because
1294 * The max_tr ring buffer has some state (e.g. ring->clock) and
1295 * we want preserve it.
1296 */
1297 ring_buffer_subbuf_order_set(tr->max_buffer.buffer, 0);
1298 ring_buffer_resize(tr->max_buffer.buffer, 1, RING_BUFFER_ALL_CPUS);
1299 set_buffer_entries(&tr->max_buffer, 1);
1300 tracing_reset_online_cpus(&tr->max_buffer);
1301 tr->allocated_snapshot = false;
1302}
1303
1304/**
1305 * tracing_alloc_snapshot - allocate snapshot buffer.
1306 *
1307 * This only allocates the snapshot buffer if it isn't already
1308 * allocated - it doesn't also take a snapshot.
1309 *
1310 * This is meant to be used in cases where the snapshot buffer needs
1311 * to be set up for events that can't sleep but need to be able to
1312 * trigger a snapshot.
1313 */
1314int tracing_alloc_snapshot(void)
1315{
1316 struct trace_array *tr = &global_trace;
1317 int ret;
1318
1319 ret = tracing_alloc_snapshot_instance(tr);
1320 WARN_ON(ret < 0);
1321
1322 return ret;
1323}
1324EXPORT_SYMBOL_GPL(tracing_alloc_snapshot);
1325
1326/**
1327 * tracing_snapshot_alloc - allocate and take a snapshot of the current buffer.
1328 *
1329 * This is similar to tracing_snapshot(), but it will allocate the
1330 * snapshot buffer if it isn't already allocated. Use this only
1331 * where it is safe to sleep, as the allocation may sleep.
1332 *
1333 * This causes a swap between the snapshot buffer and the current live
1334 * tracing buffer. You can use this to take snapshots of the live
1335 * trace when some condition is triggered, but continue to trace.
1336 */
1337void tracing_snapshot_alloc(void)
1338{
1339 int ret;
1340
1341 ret = tracing_alloc_snapshot();
1342 if (ret < 0)
1343 return;
1344
1345 tracing_snapshot();
1346}
1347EXPORT_SYMBOL_GPL(tracing_snapshot_alloc);
1348
1349/**
1350 * tracing_snapshot_cond_enable - enable conditional snapshot for an instance
1351 * @tr: The tracing instance
1352 * @cond_data: User data to associate with the snapshot
1353 * @update: Implementation of the cond_snapshot update function
1354 *
1355 * Check whether the conditional snapshot for the given instance has
1356 * already been enabled, or if the current tracer is already using a
1357 * snapshot; if so, return -EBUSY, else create a cond_snapshot and
1358 * save the cond_data and update function inside.
1359 *
1360 * Returns 0 if successful, error otherwise.
1361 */
1362int tracing_snapshot_cond_enable(struct trace_array *tr, void *cond_data,
1363 cond_update_fn_t update)
1364{
1365 struct cond_snapshot *cond_snapshot;
1366 int ret = 0;
1367
1368 cond_snapshot = kzalloc(sizeof(*cond_snapshot), GFP_KERNEL);
1369 if (!cond_snapshot)
1370 return -ENOMEM;
1371
1372 cond_snapshot->cond_data = cond_data;
1373 cond_snapshot->update = update;
1374
1375 mutex_lock(&trace_types_lock);
1376
1377 ret = tracing_alloc_snapshot_instance(tr);
1378 if (ret)
1379 goto fail_unlock;
1380
1381 if (tr->current_trace->use_max_tr) {
1382 ret = -EBUSY;
1383 goto fail_unlock;
1384 }
1385
1386 /*
1387 * The cond_snapshot can only change to NULL without the
1388 * trace_types_lock. We don't care if we race with it going
1389 * to NULL, but we want to make sure that it's not set to
1390 * something other than NULL when we get here, which we can
1391 * do safely with only holding the trace_types_lock and not
1392 * having to take the max_lock.
1393 */
1394 if (tr->cond_snapshot) {
1395 ret = -EBUSY;
1396 goto fail_unlock;
1397 }
1398
1399 local_irq_disable();
1400 arch_spin_lock(&tr->max_lock);
1401 tr->cond_snapshot = cond_snapshot;
1402 arch_spin_unlock(&tr->max_lock);
1403 local_irq_enable();
1404
1405 mutex_unlock(&trace_types_lock);
1406
1407 return ret;
1408
1409 fail_unlock:
1410 mutex_unlock(&trace_types_lock);
1411 kfree(cond_snapshot);
1412 return ret;
1413}
1414EXPORT_SYMBOL_GPL(tracing_snapshot_cond_enable);
1415
1416/**
1417 * tracing_snapshot_cond_disable - disable conditional snapshot for an instance
1418 * @tr: The tracing instance
1419 *
1420 * Check whether the conditional snapshot for the given instance is
1421 * enabled; if so, free the cond_snapshot associated with it,
1422 * otherwise return -EINVAL.
1423 *
1424 * Returns 0 if successful, error otherwise.
1425 */
1426int tracing_snapshot_cond_disable(struct trace_array *tr)
1427{
1428 int ret = 0;
1429
1430 local_irq_disable();
1431 arch_spin_lock(&tr->max_lock);
1432
1433 if (!tr->cond_snapshot)
1434 ret = -EINVAL;
1435 else {
1436 kfree(tr->cond_snapshot);
1437 tr->cond_snapshot = NULL;
1438 }
1439
1440 arch_spin_unlock(&tr->max_lock);
1441 local_irq_enable();
1442
1443 return ret;
1444}
1445EXPORT_SYMBOL_GPL(tracing_snapshot_cond_disable);
1446#else
1447void tracing_snapshot(void)
1448{
1449 WARN_ONCE(1, "Snapshot feature not enabled, but internal snapshot used");
1450}
1451EXPORT_SYMBOL_GPL(tracing_snapshot);
1452void tracing_snapshot_cond(struct trace_array *tr, void *cond_data)
1453{
1454 WARN_ONCE(1, "Snapshot feature not enabled, but internal conditional snapshot used");
1455}
1456EXPORT_SYMBOL_GPL(tracing_snapshot_cond);
1457int tracing_alloc_snapshot(void)
1458{
1459 WARN_ONCE(1, "Snapshot feature not enabled, but snapshot allocation used");
1460 return -ENODEV;
1461}
1462EXPORT_SYMBOL_GPL(tracing_alloc_snapshot);
1463void tracing_snapshot_alloc(void)
1464{
1465 /* Give warning */
1466 tracing_snapshot();
1467}
1468EXPORT_SYMBOL_GPL(tracing_snapshot_alloc);
1469void *tracing_cond_snapshot_data(struct trace_array *tr)
1470{
1471 return NULL;
1472}
1473EXPORT_SYMBOL_GPL(tracing_cond_snapshot_data);
1474int tracing_snapshot_cond_enable(struct trace_array *tr, void *cond_data, cond_update_fn_t update)
1475{
1476 return -ENODEV;
1477}
1478EXPORT_SYMBOL_GPL(tracing_snapshot_cond_enable);
1479int tracing_snapshot_cond_disable(struct trace_array *tr)
1480{
1481 return false;
1482}
1483EXPORT_SYMBOL_GPL(tracing_snapshot_cond_disable);
1484#define free_snapshot(tr) do { } while (0)
1485#endif /* CONFIG_TRACER_SNAPSHOT */
1486
1487void tracer_tracing_off(struct trace_array *tr)
1488{
1489 if (tr->array_buffer.buffer)
1490 ring_buffer_record_off(tr->array_buffer.buffer);
1491 /*
1492 * This flag is looked at when buffers haven't been allocated
1493 * yet, or by some tracers (like irqsoff), that just want to
1494 * know if the ring buffer has been disabled, but it can handle
1495 * races of where it gets disabled but we still do a record.
1496 * As the check is in the fast path of the tracers, it is more
1497 * important to be fast than accurate.
1498 */
1499 tr->buffer_disabled = 1;
1500 /* Make the flag seen by readers */
1501 smp_wmb();
1502}
1503
1504/**
1505 * tracing_off - turn off tracing buffers
1506 *
1507 * This function stops the tracing buffers from recording data.
1508 * It does not disable any overhead the tracers themselves may
1509 * be causing. This function simply causes all recording to
1510 * the ring buffers to fail.
1511 */
1512void tracing_off(void)
1513{
1514 tracer_tracing_off(&global_trace);
1515}
1516EXPORT_SYMBOL_GPL(tracing_off);
1517
1518void disable_trace_on_warning(void)
1519{
1520 if (__disable_trace_on_warning) {
1521 trace_array_printk_buf(global_trace.array_buffer.buffer, _THIS_IP_,
1522 "Disabling tracing due to warning\n");
1523 tracing_off();
1524 }
1525}
1526
1527/**
1528 * tracer_tracing_is_on - show real state of ring buffer enabled
1529 * @tr : the trace array to know if ring buffer is enabled
1530 *
1531 * Shows real state of the ring buffer if it is enabled or not.
1532 */
1533bool tracer_tracing_is_on(struct trace_array *tr)
1534{
1535 if (tr->array_buffer.buffer)
1536 return ring_buffer_record_is_set_on(tr->array_buffer.buffer);
1537 return !tr->buffer_disabled;
1538}
1539
1540/**
1541 * tracing_is_on - show state of ring buffers enabled
1542 */
1543int tracing_is_on(void)
1544{
1545 return tracer_tracing_is_on(&global_trace);
1546}
1547EXPORT_SYMBOL_GPL(tracing_is_on);
1548
1549static int __init set_buf_size(char *str)
1550{
1551 unsigned long buf_size;
1552
1553 if (!str)
1554 return 0;
1555 buf_size = memparse(str, &str);
1556 /*
1557 * nr_entries can not be zero and the startup
1558 * tests require some buffer space. Therefore
1559 * ensure we have at least 4096 bytes of buffer.
1560 */
1561 trace_buf_size = max(4096UL, buf_size);
1562 return 1;
1563}
1564__setup("trace_buf_size=", set_buf_size);
1565
1566static int __init set_tracing_thresh(char *str)
1567{
1568 unsigned long threshold;
1569 int ret;
1570
1571 if (!str)
1572 return 0;
1573 ret = kstrtoul(str, 0, &threshold);
1574 if (ret < 0)
1575 return 0;
1576 tracing_thresh = threshold * 1000;
1577 return 1;
1578}
1579__setup("tracing_thresh=", set_tracing_thresh);
1580
1581unsigned long nsecs_to_usecs(unsigned long nsecs)
1582{
1583 return nsecs / 1000;
1584}
1585
1586/*
1587 * TRACE_FLAGS is defined as a tuple matching bit masks with strings.
1588 * It uses C(a, b) where 'a' is the eval (enum) name and 'b' is the string that
1589 * matches it. By defining "C(a, b) b", TRACE_FLAGS becomes a list
1590 * of strings in the order that the evals (enum) were defined.
1591 */
1592#undef C
1593#define C(a, b) b
1594
1595/* These must match the bit positions in trace_iterator_flags */
1596static const char *trace_options[] = {
1597 TRACE_FLAGS
1598 NULL
1599};
1600
1601static struct {
1602 u64 (*func)(void);
1603 const char *name;
1604 int in_ns; /* is this clock in nanoseconds? */
1605} trace_clocks[] = {
1606 { trace_clock_local, "local", 1 },
1607 { trace_clock_global, "global", 1 },
1608 { trace_clock_counter, "counter", 0 },
1609 { trace_clock_jiffies, "uptime", 0 },
1610 { trace_clock, "perf", 1 },
1611 { ktime_get_mono_fast_ns, "mono", 1 },
1612 { ktime_get_raw_fast_ns, "mono_raw", 1 },
1613 { ktime_get_boot_fast_ns, "boot", 1 },
1614 { ktime_get_tai_fast_ns, "tai", 1 },
1615 ARCH_TRACE_CLOCKS
1616};
1617
1618bool trace_clock_in_ns(struct trace_array *tr)
1619{
1620 if (trace_clocks[tr->clock_id].in_ns)
1621 return true;
1622
1623 return false;
1624}
1625
1626/*
1627 * trace_parser_get_init - gets the buffer for trace parser
1628 */
1629int trace_parser_get_init(struct trace_parser *parser, int size)
1630{
1631 memset(parser, 0, sizeof(*parser));
1632
1633 parser->buffer = kmalloc(size, GFP_KERNEL);
1634 if (!parser->buffer)
1635 return 1;
1636
1637 parser->size = size;
1638 return 0;
1639}
1640
1641/*
1642 * trace_parser_put - frees the buffer for trace parser
1643 */
1644void trace_parser_put(struct trace_parser *parser)
1645{
1646 kfree(parser->buffer);
1647 parser->buffer = NULL;
1648}
1649
1650/*
1651 * trace_get_user - reads the user input string separated by space
1652 * (matched by isspace(ch))
1653 *
1654 * For each string found the 'struct trace_parser' is updated,
1655 * and the function returns.
1656 *
1657 * Returns number of bytes read.
1658 *
1659 * See kernel/trace/trace.h for 'struct trace_parser' details.
1660 */
1661int trace_get_user(struct trace_parser *parser, const char __user *ubuf,
1662 size_t cnt, loff_t *ppos)
1663{
1664 char ch;
1665 size_t read = 0;
1666 ssize_t ret;
1667
1668 if (!*ppos)
1669 trace_parser_clear(parser);
1670
1671 ret = get_user(ch, ubuf++);
1672 if (ret)
1673 goto out;
1674
1675 read++;
1676 cnt--;
1677
1678 /*
1679 * The parser is not finished with the last write,
1680 * continue reading the user input without skipping spaces.
1681 */
1682 if (!parser->cont) {
1683 /* skip white space */
1684 while (cnt && isspace(ch)) {
1685 ret = get_user(ch, ubuf++);
1686 if (ret)
1687 goto out;
1688 read++;
1689 cnt--;
1690 }
1691
1692 parser->idx = 0;
1693
1694 /* only spaces were written */
1695 if (isspace(ch) || !ch) {
1696 *ppos += read;
1697 ret = read;
1698 goto out;
1699 }
1700 }
1701
1702 /* read the non-space input */
1703 while (cnt && !isspace(ch) && ch) {
1704 if (parser->idx < parser->size - 1)
1705 parser->buffer[parser->idx++] = ch;
1706 else {
1707 ret = -EINVAL;
1708 goto out;
1709 }
1710 ret = get_user(ch, ubuf++);
1711 if (ret)
1712 goto out;
1713 read++;
1714 cnt--;
1715 }
1716
1717 /* We either got finished input or we have to wait for another call. */
1718 if (isspace(ch) || !ch) {
1719 parser->buffer[parser->idx] = 0;
1720 parser->cont = false;
1721 } else if (parser->idx < parser->size - 1) {
1722 parser->cont = true;
1723 parser->buffer[parser->idx++] = ch;
1724 /* Make sure the parsed string always terminates with '\0'. */
1725 parser->buffer[parser->idx] = 0;
1726 } else {
1727 ret = -EINVAL;
1728 goto out;
1729 }
1730
1731 *ppos += read;
1732 ret = read;
1733
1734out:
1735 return ret;
1736}
1737
1738/* TODO add a seq_buf_to_buffer() */
1739static ssize_t trace_seq_to_buffer(struct trace_seq *s, void *buf, size_t cnt)
1740{
1741 int len;
1742
1743 if (trace_seq_used(s) <= s->readpos)
1744 return -EBUSY;
1745
1746 len = trace_seq_used(s) - s->readpos;
1747 if (cnt > len)
1748 cnt = len;
1749 memcpy(buf, s->buffer + s->readpos, cnt);
1750
1751 s->readpos += cnt;
1752 return cnt;
1753}
1754
1755unsigned long __read_mostly tracing_thresh;
1756
1757#ifdef CONFIG_TRACER_MAX_TRACE
1758static const struct file_operations tracing_max_lat_fops;
1759
1760#ifdef LATENCY_FS_NOTIFY
1761
1762static struct workqueue_struct *fsnotify_wq;
1763
1764static void latency_fsnotify_workfn(struct work_struct *work)
1765{
1766 struct trace_array *tr = container_of(work, struct trace_array,
1767 fsnotify_work);
1768 fsnotify_inode(tr->d_max_latency->d_inode, FS_MODIFY);
1769}
1770
1771static void latency_fsnotify_workfn_irq(struct irq_work *iwork)
1772{
1773 struct trace_array *tr = container_of(iwork, struct trace_array,
1774 fsnotify_irqwork);
1775 queue_work(fsnotify_wq, &tr->fsnotify_work);
1776}
1777
1778static void trace_create_maxlat_file(struct trace_array *tr,
1779 struct dentry *d_tracer)
1780{
1781 INIT_WORK(&tr->fsnotify_work, latency_fsnotify_workfn);
1782 init_irq_work(&tr->fsnotify_irqwork, latency_fsnotify_workfn_irq);
1783 tr->d_max_latency = trace_create_file("tracing_max_latency",
1784 TRACE_MODE_WRITE,
1785 d_tracer, tr,
1786 &tracing_max_lat_fops);
1787}
1788
1789__init static int latency_fsnotify_init(void)
1790{
1791 fsnotify_wq = alloc_workqueue("tr_max_lat_wq",
1792 WQ_UNBOUND | WQ_HIGHPRI, 0);
1793 if (!fsnotify_wq) {
1794 pr_err("Unable to allocate tr_max_lat_wq\n");
1795 return -ENOMEM;
1796 }
1797 return 0;
1798}
1799
1800late_initcall_sync(latency_fsnotify_init);
1801
1802void latency_fsnotify(struct trace_array *tr)
1803{
1804 if (!fsnotify_wq)
1805 return;
1806 /*
1807 * We cannot call queue_work(&tr->fsnotify_work) from here because it's
1808 * possible that we are called from __schedule() or do_idle(), which
1809 * could cause a deadlock.
1810 */
1811 irq_work_queue(&tr->fsnotify_irqwork);
1812}
1813
1814#else /* !LATENCY_FS_NOTIFY */
1815
1816#define trace_create_maxlat_file(tr, d_tracer) \
1817 trace_create_file("tracing_max_latency", TRACE_MODE_WRITE, \
1818 d_tracer, tr, &tracing_max_lat_fops)
1819
1820#endif
1821
1822/*
1823 * Copy the new maximum trace into the separate maximum-trace
1824 * structure. (this way the maximum trace is permanently saved,
1825 * for later retrieval via /sys/kernel/tracing/tracing_max_latency)
1826 */
1827static void
1828__update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
1829{
1830 struct array_buffer *trace_buf = &tr->array_buffer;
1831 struct array_buffer *max_buf = &tr->max_buffer;
1832 struct trace_array_cpu *data = per_cpu_ptr(trace_buf->data, cpu);
1833 struct trace_array_cpu *max_data = per_cpu_ptr(max_buf->data, cpu);
1834
1835 max_buf->cpu = cpu;
1836 max_buf->time_start = data->preempt_timestamp;
1837
1838 max_data->saved_latency = tr->max_latency;
1839 max_data->critical_start = data->critical_start;
1840 max_data->critical_end = data->critical_end;
1841
1842 strncpy(max_data->comm, tsk->comm, TASK_COMM_LEN);
1843 max_data->pid = tsk->pid;
1844 /*
1845 * If tsk == current, then use current_uid(), as that does not use
1846 * RCU. The irq tracer can be called out of RCU scope.
1847 */
1848 if (tsk == current)
1849 max_data->uid = current_uid();
1850 else
1851 max_data->uid = task_uid(tsk);
1852
1853 max_data->nice = tsk->static_prio - 20 - MAX_RT_PRIO;
1854 max_data->policy = tsk->policy;
1855 max_data->rt_priority = tsk->rt_priority;
1856
1857 /* record this tasks comm */
1858 tracing_record_cmdline(tsk);
1859 latency_fsnotify(tr);
1860}
1861
1862/**
1863 * update_max_tr - snapshot all trace buffers from global_trace to max_tr
1864 * @tr: tracer
1865 * @tsk: the task with the latency
1866 * @cpu: The cpu that initiated the trace.
1867 * @cond_data: User data associated with a conditional snapshot
1868 *
1869 * Flip the buffers between the @tr and the max_tr and record information
1870 * about which task was the cause of this latency.
1871 */
1872void
1873update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu,
1874 void *cond_data)
1875{
1876 if (tr->stop_count)
1877 return;
1878
1879 WARN_ON_ONCE(!irqs_disabled());
1880
1881 if (!tr->allocated_snapshot) {
1882 /* Only the nop tracer should hit this when disabling */
1883 WARN_ON_ONCE(tr->current_trace != &nop_trace);
1884 return;
1885 }
1886
1887 arch_spin_lock(&tr->max_lock);
1888
1889 /* Inherit the recordable setting from array_buffer */
1890 if (ring_buffer_record_is_set_on(tr->array_buffer.buffer))
1891 ring_buffer_record_on(tr->max_buffer.buffer);
1892 else
1893 ring_buffer_record_off(tr->max_buffer.buffer);
1894
1895#ifdef CONFIG_TRACER_SNAPSHOT
1896 if (tr->cond_snapshot && !tr->cond_snapshot->update(tr, cond_data)) {
1897 arch_spin_unlock(&tr->max_lock);
1898 return;
1899 }
1900#endif
1901 swap(tr->array_buffer.buffer, tr->max_buffer.buffer);
1902
1903 __update_max_tr(tr, tsk, cpu);
1904
1905 arch_spin_unlock(&tr->max_lock);
1906
1907 /* Any waiters on the old snapshot buffer need to wake up */
1908 ring_buffer_wake_waiters(tr->array_buffer.buffer, RING_BUFFER_ALL_CPUS);
1909}
1910
1911/**
1912 * update_max_tr_single - only copy one trace over, and reset the rest
1913 * @tr: tracer
1914 * @tsk: task with the latency
1915 * @cpu: the cpu of the buffer to copy.
1916 *
1917 * Flip the trace of a single CPU buffer between the @tr and the max_tr.
1918 */
1919void
1920update_max_tr_single(struct trace_array *tr, struct task_struct *tsk, int cpu)
1921{
1922 int ret;
1923
1924 if (tr->stop_count)
1925 return;
1926
1927 WARN_ON_ONCE(!irqs_disabled());
1928 if (!tr->allocated_snapshot) {
1929 /* Only the nop tracer should hit this when disabling */
1930 WARN_ON_ONCE(tr->current_trace != &nop_trace);
1931 return;
1932 }
1933
1934 arch_spin_lock(&tr->max_lock);
1935
1936 ret = ring_buffer_swap_cpu(tr->max_buffer.buffer, tr->array_buffer.buffer, cpu);
1937
1938 if (ret == -EBUSY) {
1939 /*
1940 * We failed to swap the buffer due to a commit taking
1941 * place on this CPU. We fail to record, but we reset
1942 * the max trace buffer (no one writes directly to it)
1943 * and flag that it failed.
1944 * Another reason is resize is in progress.
1945 */
1946 trace_array_printk_buf(tr->max_buffer.buffer, _THIS_IP_,
1947 "Failed to swap buffers due to commit or resize in progress\n");
1948 }
1949
1950 WARN_ON_ONCE(ret && ret != -EAGAIN && ret != -EBUSY);
1951
1952 __update_max_tr(tr, tsk, cpu);
1953 arch_spin_unlock(&tr->max_lock);
1954}
1955
1956#endif /* CONFIG_TRACER_MAX_TRACE */
1957
1958static int wait_on_pipe(struct trace_iterator *iter, int full)
1959{
1960 int ret;
1961
1962 /* Iterators are static, they should be filled or empty */
1963 if (trace_buffer_iter(iter, iter->cpu_file))
1964 return 0;
1965
1966 ret = ring_buffer_wait(iter->array_buffer->buffer, iter->cpu_file, full);
1967
1968#ifdef CONFIG_TRACER_MAX_TRACE
1969 /*
1970 * Make sure this is still the snapshot buffer, as if a snapshot were
1971 * to happen, this would now be the main buffer.
1972 */
1973 if (iter->snapshot)
1974 iter->array_buffer = &iter->tr->max_buffer;
1975#endif
1976 return ret;
1977}
1978
1979#ifdef CONFIG_FTRACE_STARTUP_TEST
1980static bool selftests_can_run;
1981
1982struct trace_selftests {
1983 struct list_head list;
1984 struct tracer *type;
1985};
1986
1987static LIST_HEAD(postponed_selftests);
1988
1989static int save_selftest(struct tracer *type)
1990{
1991 struct trace_selftests *selftest;
1992
1993 selftest = kmalloc(sizeof(*selftest), GFP_KERNEL);
1994 if (!selftest)
1995 return -ENOMEM;
1996
1997 selftest->type = type;
1998 list_add(&selftest->list, &postponed_selftests);
1999 return 0;
2000}
2001
2002static int run_tracer_selftest(struct tracer *type)
2003{
2004 struct trace_array *tr = &global_trace;
2005 struct tracer *saved_tracer = tr->current_trace;
2006 int ret;
2007
2008 if (!type->selftest || tracing_selftest_disabled)
2009 return 0;
2010
2011 /*
2012 * If a tracer registers early in boot up (before scheduling is
2013 * initialized and such), then do not run its selftests yet.
2014 * Instead, run it a little later in the boot process.
2015 */
2016 if (!selftests_can_run)
2017 return save_selftest(type);
2018
2019 if (!tracing_is_on()) {
2020 pr_warn("Selftest for tracer %s skipped due to tracing disabled\n",
2021 type->name);
2022 return 0;
2023 }
2024
2025 /*
2026 * Run a selftest on this tracer.
2027 * Here we reset the trace buffer, and set the current
2028 * tracer to be this tracer. The tracer can then run some
2029 * internal tracing to verify that everything is in order.
2030 * If we fail, we do not register this tracer.
2031 */
2032 tracing_reset_online_cpus(&tr->array_buffer);
2033
2034 tr->current_trace = type;
2035
2036#ifdef CONFIG_TRACER_MAX_TRACE
2037 if (type->use_max_tr) {
2038 /* If we expanded the buffers, make sure the max is expanded too */
2039 if (tr->ring_buffer_expanded)
2040 ring_buffer_resize(tr->max_buffer.buffer, trace_buf_size,
2041 RING_BUFFER_ALL_CPUS);
2042 tr->allocated_snapshot = true;
2043 }
2044#endif
2045
2046 /* the test is responsible for initializing and enabling */
2047 pr_info("Testing tracer %s: ", type->name);
2048 ret = type->selftest(type, tr);
2049 /* the test is responsible for resetting too */
2050 tr->current_trace = saved_tracer;
2051 if (ret) {
2052 printk(KERN_CONT "FAILED!\n");
2053 /* Add the warning after printing 'FAILED' */
2054 WARN_ON(1);
2055 return -1;
2056 }
2057 /* Only reset on passing, to avoid touching corrupted buffers */
2058 tracing_reset_online_cpus(&tr->array_buffer);
2059
2060#ifdef CONFIG_TRACER_MAX_TRACE
2061 if (type->use_max_tr) {
2062 tr->allocated_snapshot = false;
2063
2064 /* Shrink the max buffer again */
2065 if (tr->ring_buffer_expanded)
2066 ring_buffer_resize(tr->max_buffer.buffer, 1,
2067 RING_BUFFER_ALL_CPUS);
2068 }
2069#endif
2070
2071 printk(KERN_CONT "PASSED\n");
2072 return 0;
2073}
2074
2075static int do_run_tracer_selftest(struct tracer *type)
2076{
2077 int ret;
2078
2079 /*
2080 * Tests can take a long time, especially if they are run one after the
2081 * other, as does happen during bootup when all the tracers are
2082 * registered. This could cause the soft lockup watchdog to trigger.
2083 */
2084 cond_resched();
2085
2086 tracing_selftest_running = true;
2087 ret = run_tracer_selftest(type);
2088 tracing_selftest_running = false;
2089
2090 return ret;
2091}
2092
2093static __init int init_trace_selftests(void)
2094{
2095 struct trace_selftests *p, *n;
2096 struct tracer *t, **last;
2097 int ret;
2098
2099 selftests_can_run = true;
2100
2101 mutex_lock(&trace_types_lock);
2102
2103 if (list_empty(&postponed_selftests))
2104 goto out;
2105
2106 pr_info("Running postponed tracer tests:\n");
2107
2108 tracing_selftest_running = true;
2109 list_for_each_entry_safe(p, n, &postponed_selftests, list) {
2110 /* This loop can take minutes when sanitizers are enabled, so
2111 * lets make sure we allow RCU processing.
2112 */
2113 cond_resched();
2114 ret = run_tracer_selftest(p->type);
2115 /* If the test fails, then warn and remove from available_tracers */
2116 if (ret < 0) {
2117 WARN(1, "tracer: %s failed selftest, disabling\n",
2118 p->type->name);
2119 last = &trace_types;
2120 for (t = trace_types; t; t = t->next) {
2121 if (t == p->type) {
2122 *last = t->next;
2123 break;
2124 }
2125 last = &t->next;
2126 }
2127 }
2128 list_del(&p->list);
2129 kfree(p);
2130 }
2131 tracing_selftest_running = false;
2132
2133 out:
2134 mutex_unlock(&trace_types_lock);
2135
2136 return 0;
2137}
2138core_initcall(init_trace_selftests);
2139#else
2140static inline int run_tracer_selftest(struct tracer *type)
2141{
2142 return 0;
2143}
2144static inline int do_run_tracer_selftest(struct tracer *type)
2145{
2146 return 0;
2147}
2148#endif /* CONFIG_FTRACE_STARTUP_TEST */
2149
2150static void add_tracer_options(struct trace_array *tr, struct tracer *t);
2151
2152static void __init apply_trace_boot_options(void);
2153
2154/**
2155 * register_tracer - register a tracer with the ftrace system.
2156 * @type: the plugin for the tracer
2157 *
2158 * Register a new plugin tracer.
2159 */
2160int __init register_tracer(struct tracer *type)
2161{
2162 struct tracer *t;
2163 int ret = 0;
2164
2165 if (!type->name) {
2166 pr_info("Tracer must have a name\n");
2167 return -1;
2168 }
2169
2170 if (strlen(type->name) >= MAX_TRACER_SIZE) {
2171 pr_info("Tracer has a name longer than %d\n", MAX_TRACER_SIZE);
2172 return -1;
2173 }
2174
2175 if (security_locked_down(LOCKDOWN_TRACEFS)) {
2176 pr_warn("Can not register tracer %s due to lockdown\n",
2177 type->name);
2178 return -EPERM;
2179 }
2180
2181 mutex_lock(&trace_types_lock);
2182
2183 for (t = trace_types; t; t = t->next) {
2184 if (strcmp(type->name, t->name) == 0) {
2185 /* already found */
2186 pr_info("Tracer %s already registered\n",
2187 type->name);
2188 ret = -1;
2189 goto out;
2190 }
2191 }
2192
2193 if (!type->set_flag)
2194 type->set_flag = &dummy_set_flag;
2195 if (!type->flags) {
2196 /*allocate a dummy tracer_flags*/
2197 type->flags = kmalloc(sizeof(*type->flags), GFP_KERNEL);
2198 if (!type->flags) {
2199 ret = -ENOMEM;
2200 goto out;
2201 }
2202 type->flags->val = 0;
2203 type->flags->opts = dummy_tracer_opt;
2204 } else
2205 if (!type->flags->opts)
2206 type->flags->opts = dummy_tracer_opt;
2207
2208 /* store the tracer for __set_tracer_option */
2209 type->flags->trace = type;
2210
2211 ret = do_run_tracer_selftest(type);
2212 if (ret < 0)
2213 goto out;
2214
2215 type->next = trace_types;
2216 trace_types = type;
2217 add_tracer_options(&global_trace, type);
2218
2219 out:
2220 mutex_unlock(&trace_types_lock);
2221
2222 if (ret || !default_bootup_tracer)
2223 goto out_unlock;
2224
2225 if (strncmp(default_bootup_tracer, type->name, MAX_TRACER_SIZE))
2226 goto out_unlock;
2227
2228 printk(KERN_INFO "Starting tracer '%s'\n", type->name);
2229 /* Do we want this tracer to start on bootup? */
2230 tracing_set_tracer(&global_trace, type->name);
2231 default_bootup_tracer = NULL;
2232
2233 apply_trace_boot_options();
2234
2235 /* disable other selftests, since this will break it. */
2236 disable_tracing_selftest("running a tracer");
2237
2238 out_unlock:
2239 return ret;
2240}
2241
2242static void tracing_reset_cpu(struct array_buffer *buf, int cpu)
2243{
2244 struct trace_buffer *buffer = buf->buffer;
2245
2246 if (!buffer)
2247 return;
2248
2249 ring_buffer_record_disable(buffer);
2250
2251 /* Make sure all commits have finished */
2252 synchronize_rcu();
2253 ring_buffer_reset_cpu(buffer, cpu);
2254
2255 ring_buffer_record_enable(buffer);
2256}
2257
2258void tracing_reset_online_cpus(struct array_buffer *buf)
2259{
2260 struct trace_buffer *buffer = buf->buffer;
2261
2262 if (!buffer)
2263 return;
2264
2265 ring_buffer_record_disable(buffer);
2266
2267 /* Make sure all commits have finished */
2268 synchronize_rcu();
2269
2270 buf->time_start = buffer_ftrace_now(buf, buf->cpu);
2271
2272 ring_buffer_reset_online_cpus(buffer);
2273
2274 ring_buffer_record_enable(buffer);
2275}
2276
2277/* Must have trace_types_lock held */
2278void tracing_reset_all_online_cpus_unlocked(void)
2279{
2280 struct trace_array *tr;
2281
2282 lockdep_assert_held(&trace_types_lock);
2283
2284 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
2285 if (!tr->clear_trace)
2286 continue;
2287 tr->clear_trace = false;
2288 tracing_reset_online_cpus(&tr->array_buffer);
2289#ifdef CONFIG_TRACER_MAX_TRACE
2290 tracing_reset_online_cpus(&tr->max_buffer);
2291#endif
2292 }
2293}
2294
2295void tracing_reset_all_online_cpus(void)
2296{
2297 mutex_lock(&trace_types_lock);
2298 tracing_reset_all_online_cpus_unlocked();
2299 mutex_unlock(&trace_types_lock);
2300}
2301
2302/*
2303 * The tgid_map array maps from pid to tgid; i.e. the value stored at index i
2304 * is the tgid last observed corresponding to pid=i.
2305 */
2306static int *tgid_map;
2307
2308/* The maximum valid index into tgid_map. */
2309static size_t tgid_map_max;
2310
2311#define SAVED_CMDLINES_DEFAULT 128
2312#define NO_CMDLINE_MAP UINT_MAX
2313/*
2314 * Preemption must be disabled before acquiring trace_cmdline_lock.
2315 * The various trace_arrays' max_lock must be acquired in a context
2316 * where interrupt is disabled.
2317 */
2318static arch_spinlock_t trace_cmdline_lock = __ARCH_SPIN_LOCK_UNLOCKED;
2319struct saved_cmdlines_buffer {
2320 unsigned map_pid_to_cmdline[PID_MAX_DEFAULT+1];
2321 unsigned *map_cmdline_to_pid;
2322 unsigned cmdline_num;
2323 int cmdline_idx;
2324 char saved_cmdlines[];
2325};
2326static struct saved_cmdlines_buffer *savedcmd;
2327
2328static inline char *get_saved_cmdlines(int idx)
2329{
2330 return &savedcmd->saved_cmdlines[idx * TASK_COMM_LEN];
2331}
2332
2333static inline void set_cmdline(int idx, const char *cmdline)
2334{
2335 strncpy(get_saved_cmdlines(idx), cmdline, TASK_COMM_LEN);
2336}
2337
2338static void free_saved_cmdlines_buffer(struct saved_cmdlines_buffer *s)
2339{
2340 int order = get_order(sizeof(*s) + s->cmdline_num * TASK_COMM_LEN);
2341
2342 kfree(s->map_cmdline_to_pid);
2343 kmemleak_free(s);
2344 free_pages((unsigned long)s, order);
2345}
2346
2347static struct saved_cmdlines_buffer *allocate_cmdlines_buffer(unsigned int val)
2348{
2349 struct saved_cmdlines_buffer *s;
2350 struct page *page;
2351 int orig_size, size;
2352 int order;
2353
2354 /* Figure out how much is needed to hold the given number of cmdlines */
2355 orig_size = sizeof(*s) + val * TASK_COMM_LEN;
2356 order = get_order(orig_size);
2357 size = 1 << (order + PAGE_SHIFT);
2358 page = alloc_pages(GFP_KERNEL, order);
2359 if (!page)
2360 return NULL;
2361
2362 s = page_address(page);
2363 kmemleak_alloc(s, size, 1, GFP_KERNEL);
2364 memset(s, 0, sizeof(*s));
2365
2366 /* Round up to actual allocation */
2367 val = (size - sizeof(*s)) / TASK_COMM_LEN;
2368 s->cmdline_num = val;
2369
2370 s->map_cmdline_to_pid = kmalloc_array(val,
2371 sizeof(*s->map_cmdline_to_pid),
2372 GFP_KERNEL);
2373 if (!s->map_cmdline_to_pid) {
2374 free_saved_cmdlines_buffer(s);
2375 return NULL;
2376 }
2377
2378 s->cmdline_idx = 0;
2379 memset(&s->map_pid_to_cmdline, NO_CMDLINE_MAP,
2380 sizeof(s->map_pid_to_cmdline));
2381 memset(s->map_cmdline_to_pid, NO_CMDLINE_MAP,
2382 val * sizeof(*s->map_cmdline_to_pid));
2383
2384 return s;
2385}
2386
2387static int trace_create_savedcmd(void)
2388{
2389 savedcmd = allocate_cmdlines_buffer(SAVED_CMDLINES_DEFAULT);
2390
2391 return savedcmd ? 0 : -ENOMEM;
2392}
2393
2394int is_tracing_stopped(void)
2395{
2396 return global_trace.stop_count;
2397}
2398
2399static void tracing_start_tr(struct trace_array *tr)
2400{
2401 struct trace_buffer *buffer;
2402 unsigned long flags;
2403
2404 if (tracing_disabled)
2405 return;
2406
2407 raw_spin_lock_irqsave(&tr->start_lock, flags);
2408 if (--tr->stop_count) {
2409 if (WARN_ON_ONCE(tr->stop_count < 0)) {
2410 /* Someone screwed up their debugging */
2411 tr->stop_count = 0;
2412 }
2413 goto out;
2414 }
2415
2416 /* Prevent the buffers from switching */
2417 arch_spin_lock(&tr->max_lock);
2418
2419 buffer = tr->array_buffer.buffer;
2420 if (buffer)
2421 ring_buffer_record_enable(buffer);
2422
2423#ifdef CONFIG_TRACER_MAX_TRACE
2424 buffer = tr->max_buffer.buffer;
2425 if (buffer)
2426 ring_buffer_record_enable(buffer);
2427#endif
2428
2429 arch_spin_unlock(&tr->max_lock);
2430
2431 out:
2432 raw_spin_unlock_irqrestore(&tr->start_lock, flags);
2433}
2434
2435/**
2436 * tracing_start - quick start of the tracer
2437 *
2438 * If tracing is enabled but was stopped by tracing_stop,
2439 * this will start the tracer back up.
2440 */
2441void tracing_start(void)
2442
2443{
2444 return tracing_start_tr(&global_trace);
2445}
2446
2447static void tracing_stop_tr(struct trace_array *tr)
2448{
2449 struct trace_buffer *buffer;
2450 unsigned long flags;
2451
2452 raw_spin_lock_irqsave(&tr->start_lock, flags);
2453 if (tr->stop_count++)
2454 goto out;
2455
2456 /* Prevent the buffers from switching */
2457 arch_spin_lock(&tr->max_lock);
2458
2459 buffer = tr->array_buffer.buffer;
2460 if (buffer)
2461 ring_buffer_record_disable(buffer);
2462
2463#ifdef CONFIG_TRACER_MAX_TRACE
2464 buffer = tr->max_buffer.buffer;
2465 if (buffer)
2466 ring_buffer_record_disable(buffer);
2467#endif
2468
2469 arch_spin_unlock(&tr->max_lock);
2470
2471 out:
2472 raw_spin_unlock_irqrestore(&tr->start_lock, flags);
2473}
2474
2475/**
2476 * tracing_stop - quick stop of the tracer
2477 *
2478 * Light weight way to stop tracing. Use in conjunction with
2479 * tracing_start.
2480 */
2481void tracing_stop(void)
2482{
2483 return tracing_stop_tr(&global_trace);
2484}
2485
2486static int trace_save_cmdline(struct task_struct *tsk)
2487{
2488 unsigned tpid, idx;
2489
2490 /* treat recording of idle task as a success */
2491 if (!tsk->pid)
2492 return 1;
2493
2494 tpid = tsk->pid & (PID_MAX_DEFAULT - 1);
2495
2496 /*
2497 * It's not the end of the world if we don't get
2498 * the lock, but we also don't want to spin
2499 * nor do we want to disable interrupts,
2500 * so if we miss here, then better luck next time.
2501 *
2502 * This is called within the scheduler and wake up, so interrupts
2503 * had better been disabled and run queue lock been held.
2504 */
2505 lockdep_assert_preemption_disabled();
2506 if (!arch_spin_trylock(&trace_cmdline_lock))
2507 return 0;
2508
2509 idx = savedcmd->map_pid_to_cmdline[tpid];
2510 if (idx == NO_CMDLINE_MAP) {
2511 idx = (savedcmd->cmdline_idx + 1) % savedcmd->cmdline_num;
2512
2513 savedcmd->map_pid_to_cmdline[tpid] = idx;
2514 savedcmd->cmdline_idx = idx;
2515 }
2516
2517 savedcmd->map_cmdline_to_pid[idx] = tsk->pid;
2518 set_cmdline(idx, tsk->comm);
2519
2520 arch_spin_unlock(&trace_cmdline_lock);
2521
2522 return 1;
2523}
2524
2525static void __trace_find_cmdline(int pid, char comm[])
2526{
2527 unsigned map;
2528 int tpid;
2529
2530 if (!pid) {
2531 strcpy(comm, "<idle>");
2532 return;
2533 }
2534
2535 if (WARN_ON_ONCE(pid < 0)) {
2536 strcpy(comm, "<XXX>");
2537 return;
2538 }
2539
2540 tpid = pid & (PID_MAX_DEFAULT - 1);
2541 map = savedcmd->map_pid_to_cmdline[tpid];
2542 if (map != NO_CMDLINE_MAP) {
2543 tpid = savedcmd->map_cmdline_to_pid[map];
2544 if (tpid == pid) {
2545 strscpy(comm, get_saved_cmdlines(map), TASK_COMM_LEN);
2546 return;
2547 }
2548 }
2549 strcpy(comm, "<...>");
2550}
2551
2552void trace_find_cmdline(int pid, char comm[])
2553{
2554 preempt_disable();
2555 arch_spin_lock(&trace_cmdline_lock);
2556
2557 __trace_find_cmdline(pid, comm);
2558
2559 arch_spin_unlock(&trace_cmdline_lock);
2560 preempt_enable();
2561}
2562
2563static int *trace_find_tgid_ptr(int pid)
2564{
2565 /*
2566 * Pairs with the smp_store_release in set_tracer_flag() to ensure that
2567 * if we observe a non-NULL tgid_map then we also observe the correct
2568 * tgid_map_max.
2569 */
2570 int *map = smp_load_acquire(&tgid_map);
2571
2572 if (unlikely(!map || pid > tgid_map_max))
2573 return NULL;
2574
2575 return &map[pid];
2576}
2577
2578int trace_find_tgid(int pid)
2579{
2580 int *ptr = trace_find_tgid_ptr(pid);
2581
2582 return ptr ? *ptr : 0;
2583}
2584
2585static int trace_save_tgid(struct task_struct *tsk)
2586{
2587 int *ptr;
2588
2589 /* treat recording of idle task as a success */
2590 if (!tsk->pid)
2591 return 1;
2592
2593 ptr = trace_find_tgid_ptr(tsk->pid);
2594 if (!ptr)
2595 return 0;
2596
2597 *ptr = tsk->tgid;
2598 return 1;
2599}
2600
2601static bool tracing_record_taskinfo_skip(int flags)
2602{
2603 if (unlikely(!(flags & (TRACE_RECORD_CMDLINE | TRACE_RECORD_TGID))))
2604 return true;
2605 if (!__this_cpu_read(trace_taskinfo_save))
2606 return true;
2607 return false;
2608}
2609
2610/**
2611 * tracing_record_taskinfo - record the task info of a task
2612 *
2613 * @task: task to record
2614 * @flags: TRACE_RECORD_CMDLINE for recording comm
2615 * TRACE_RECORD_TGID for recording tgid
2616 */
2617void tracing_record_taskinfo(struct task_struct *task, int flags)
2618{
2619 bool done;
2620
2621 if (tracing_record_taskinfo_skip(flags))
2622 return;
2623
2624 /*
2625 * Record as much task information as possible. If some fail, continue
2626 * to try to record the others.
2627 */
2628 done = !(flags & TRACE_RECORD_CMDLINE) || trace_save_cmdline(task);
2629 done &= !(flags & TRACE_RECORD_TGID) || trace_save_tgid(task);
2630
2631 /* If recording any information failed, retry again soon. */
2632 if (!done)
2633 return;
2634
2635 __this_cpu_write(trace_taskinfo_save, false);
2636}
2637
2638/**
2639 * tracing_record_taskinfo_sched_switch - record task info for sched_switch
2640 *
2641 * @prev: previous task during sched_switch
2642 * @next: next task during sched_switch
2643 * @flags: TRACE_RECORD_CMDLINE for recording comm
2644 * TRACE_RECORD_TGID for recording tgid
2645 */
2646void tracing_record_taskinfo_sched_switch(struct task_struct *prev,
2647 struct task_struct *next, int flags)
2648{
2649 bool done;
2650
2651 if (tracing_record_taskinfo_skip(flags))
2652 return;
2653
2654 /*
2655 * Record as much task information as possible. If some fail, continue
2656 * to try to record the others.
2657 */
2658 done = !(flags & TRACE_RECORD_CMDLINE) || trace_save_cmdline(prev);
2659 done &= !(flags & TRACE_RECORD_CMDLINE) || trace_save_cmdline(next);
2660 done &= !(flags & TRACE_RECORD_TGID) || trace_save_tgid(prev);
2661 done &= !(flags & TRACE_RECORD_TGID) || trace_save_tgid(next);
2662
2663 /* If recording any information failed, retry again soon. */
2664 if (!done)
2665 return;
2666
2667 __this_cpu_write(trace_taskinfo_save, false);
2668}
2669
2670/* Helpers to record a specific task information */
2671void tracing_record_cmdline(struct task_struct *task)
2672{
2673 tracing_record_taskinfo(task, TRACE_RECORD_CMDLINE);
2674}
2675
2676void tracing_record_tgid(struct task_struct *task)
2677{
2678 tracing_record_taskinfo(task, TRACE_RECORD_TGID);
2679}
2680
2681/*
2682 * Several functions return TRACE_TYPE_PARTIAL_LINE if the trace_seq
2683 * overflowed, and TRACE_TYPE_HANDLED otherwise. This helper function
2684 * simplifies those functions and keeps them in sync.
2685 */
2686enum print_line_t trace_handle_return(struct trace_seq *s)
2687{
2688 return trace_seq_has_overflowed(s) ?
2689 TRACE_TYPE_PARTIAL_LINE : TRACE_TYPE_HANDLED;
2690}
2691EXPORT_SYMBOL_GPL(trace_handle_return);
2692
2693static unsigned short migration_disable_value(void)
2694{
2695#if defined(CONFIG_SMP)
2696 return current->migration_disabled;
2697#else
2698 return 0;
2699#endif
2700}
2701
2702unsigned int tracing_gen_ctx_irq_test(unsigned int irqs_status)
2703{
2704 unsigned int trace_flags = irqs_status;
2705 unsigned int pc;
2706
2707 pc = preempt_count();
2708
2709 if (pc & NMI_MASK)
2710 trace_flags |= TRACE_FLAG_NMI;
2711 if (pc & HARDIRQ_MASK)
2712 trace_flags |= TRACE_FLAG_HARDIRQ;
2713 if (in_serving_softirq())
2714 trace_flags |= TRACE_FLAG_SOFTIRQ;
2715 if (softirq_count() >> (SOFTIRQ_SHIFT + 1))
2716 trace_flags |= TRACE_FLAG_BH_OFF;
2717
2718 if (tif_need_resched())
2719 trace_flags |= TRACE_FLAG_NEED_RESCHED;
2720 if (test_preempt_need_resched())
2721 trace_flags |= TRACE_FLAG_PREEMPT_RESCHED;
2722 return (trace_flags << 16) | (min_t(unsigned int, pc & 0xff, 0xf)) |
2723 (min_t(unsigned int, migration_disable_value(), 0xf)) << 4;
2724}
2725
2726struct ring_buffer_event *
2727trace_buffer_lock_reserve(struct trace_buffer *buffer,
2728 int type,
2729 unsigned long len,
2730 unsigned int trace_ctx)
2731{
2732 return __trace_buffer_lock_reserve(buffer, type, len, trace_ctx);
2733}
2734
2735DEFINE_PER_CPU(struct ring_buffer_event *, trace_buffered_event);
2736DEFINE_PER_CPU(int, trace_buffered_event_cnt);
2737static int trace_buffered_event_ref;
2738
2739/**
2740 * trace_buffered_event_enable - enable buffering events
2741 *
2742 * When events are being filtered, it is quicker to use a temporary
2743 * buffer to write the event data into if there's a likely chance
2744 * that it will not be committed. The discard of the ring buffer
2745 * is not as fast as committing, and is much slower than copying
2746 * a commit.
2747 *
2748 * When an event is to be filtered, allocate per cpu buffers to
2749 * write the event data into, and if the event is filtered and discarded
2750 * it is simply dropped, otherwise, the entire data is to be committed
2751 * in one shot.
2752 */
2753void trace_buffered_event_enable(void)
2754{
2755 struct ring_buffer_event *event;
2756 struct page *page;
2757 int cpu;
2758
2759 WARN_ON_ONCE(!mutex_is_locked(&event_mutex));
2760
2761 if (trace_buffered_event_ref++)
2762 return;
2763
2764 for_each_tracing_cpu(cpu) {
2765 page = alloc_pages_node(cpu_to_node(cpu),
2766 GFP_KERNEL | __GFP_NORETRY, 0);
2767 /* This is just an optimization and can handle failures */
2768 if (!page) {
2769 pr_err("Failed to allocate event buffer\n");
2770 break;
2771 }
2772
2773 event = page_address(page);
2774 memset(event, 0, sizeof(*event));
2775
2776 per_cpu(trace_buffered_event, cpu) = event;
2777
2778 preempt_disable();
2779 if (cpu == smp_processor_id() &&
2780 __this_cpu_read(trace_buffered_event) !=
2781 per_cpu(trace_buffered_event, cpu))
2782 WARN_ON_ONCE(1);
2783 preempt_enable();
2784 }
2785}
2786
2787static void enable_trace_buffered_event(void *data)
2788{
2789 /* Probably not needed, but do it anyway */
2790 smp_rmb();
2791 this_cpu_dec(trace_buffered_event_cnt);
2792}
2793
2794static void disable_trace_buffered_event(void *data)
2795{
2796 this_cpu_inc(trace_buffered_event_cnt);
2797}
2798
2799/**
2800 * trace_buffered_event_disable - disable buffering events
2801 *
2802 * When a filter is removed, it is faster to not use the buffered
2803 * events, and to commit directly into the ring buffer. Free up
2804 * the temp buffers when there are no more users. This requires
2805 * special synchronization with current events.
2806 */
2807void trace_buffered_event_disable(void)
2808{
2809 int cpu;
2810
2811 WARN_ON_ONCE(!mutex_is_locked(&event_mutex));
2812
2813 if (WARN_ON_ONCE(!trace_buffered_event_ref))
2814 return;
2815
2816 if (--trace_buffered_event_ref)
2817 return;
2818
2819 /* For each CPU, set the buffer as used. */
2820 on_each_cpu_mask(tracing_buffer_mask, disable_trace_buffered_event,
2821 NULL, true);
2822
2823 /* Wait for all current users to finish */
2824 synchronize_rcu();
2825
2826 for_each_tracing_cpu(cpu) {
2827 free_page((unsigned long)per_cpu(trace_buffered_event, cpu));
2828 per_cpu(trace_buffered_event, cpu) = NULL;
2829 }
2830
2831 /*
2832 * Wait for all CPUs that potentially started checking if they can use
2833 * their event buffer only after the previous synchronize_rcu() call and
2834 * they still read a valid pointer from trace_buffered_event. It must be
2835 * ensured they don't see cleared trace_buffered_event_cnt else they
2836 * could wrongly decide to use the pointed-to buffer which is now freed.
2837 */
2838 synchronize_rcu();
2839
2840 /* For each CPU, relinquish the buffer */
2841 on_each_cpu_mask(tracing_buffer_mask, enable_trace_buffered_event, NULL,
2842 true);
2843}
2844
2845static struct trace_buffer *temp_buffer;
2846
2847struct ring_buffer_event *
2848trace_event_buffer_lock_reserve(struct trace_buffer **current_rb,
2849 struct trace_event_file *trace_file,
2850 int type, unsigned long len,
2851 unsigned int trace_ctx)
2852{
2853 struct ring_buffer_event *entry;
2854 struct trace_array *tr = trace_file->tr;
2855 int val;
2856
2857 *current_rb = tr->array_buffer.buffer;
2858
2859 if (!tr->no_filter_buffering_ref &&
2860 (trace_file->flags & (EVENT_FILE_FL_SOFT_DISABLED | EVENT_FILE_FL_FILTERED))) {
2861 preempt_disable_notrace();
2862 /*
2863 * Filtering is on, so try to use the per cpu buffer first.
2864 * This buffer will simulate a ring_buffer_event,
2865 * where the type_len is zero and the array[0] will
2866 * hold the full length.
2867 * (see include/linux/ring-buffer.h for details on
2868 * how the ring_buffer_event is structured).
2869 *
2870 * Using a temp buffer during filtering and copying it
2871 * on a matched filter is quicker than writing directly
2872 * into the ring buffer and then discarding it when
2873 * it doesn't match. That is because the discard
2874 * requires several atomic operations to get right.
2875 * Copying on match and doing nothing on a failed match
2876 * is still quicker than no copy on match, but having
2877 * to discard out of the ring buffer on a failed match.
2878 */
2879 if ((entry = __this_cpu_read(trace_buffered_event))) {
2880 int max_len = PAGE_SIZE - struct_size(entry, array, 1);
2881
2882 val = this_cpu_inc_return(trace_buffered_event_cnt);
2883
2884 /*
2885 * Preemption is disabled, but interrupts and NMIs
2886 * can still come in now. If that happens after
2887 * the above increment, then it will have to go
2888 * back to the old method of allocating the event
2889 * on the ring buffer, and if the filter fails, it
2890 * will have to call ring_buffer_discard_commit()
2891 * to remove it.
2892 *
2893 * Need to also check the unlikely case that the
2894 * length is bigger than the temp buffer size.
2895 * If that happens, then the reserve is pretty much
2896 * guaranteed to fail, as the ring buffer currently
2897 * only allows events less than a page. But that may
2898 * change in the future, so let the ring buffer reserve
2899 * handle the failure in that case.
2900 */
2901 if (val == 1 && likely(len <= max_len)) {
2902 trace_event_setup(entry, type, trace_ctx);
2903 entry->array[0] = len;
2904 /* Return with preemption disabled */
2905 return entry;
2906 }
2907 this_cpu_dec(trace_buffered_event_cnt);
2908 }
2909 /* __trace_buffer_lock_reserve() disables preemption */
2910 preempt_enable_notrace();
2911 }
2912
2913 entry = __trace_buffer_lock_reserve(*current_rb, type, len,
2914 trace_ctx);
2915 /*
2916 * If tracing is off, but we have triggers enabled
2917 * we still need to look at the event data. Use the temp_buffer
2918 * to store the trace event for the trigger to use. It's recursive
2919 * safe and will not be recorded anywhere.
2920 */
2921 if (!entry && trace_file->flags & EVENT_FILE_FL_TRIGGER_COND) {
2922 *current_rb = temp_buffer;
2923 entry = __trace_buffer_lock_reserve(*current_rb, type, len,
2924 trace_ctx);
2925 }
2926 return entry;
2927}
2928EXPORT_SYMBOL_GPL(trace_event_buffer_lock_reserve);
2929
2930static DEFINE_RAW_SPINLOCK(tracepoint_iter_lock);
2931static DEFINE_MUTEX(tracepoint_printk_mutex);
2932
2933static void output_printk(struct trace_event_buffer *fbuffer)
2934{
2935 struct trace_event_call *event_call;
2936 struct trace_event_file *file;
2937 struct trace_event *event;
2938 unsigned long flags;
2939 struct trace_iterator *iter = tracepoint_print_iter;
2940
2941 /* We should never get here if iter is NULL */
2942 if (WARN_ON_ONCE(!iter))
2943 return;
2944
2945 event_call = fbuffer->trace_file->event_call;
2946 if (!event_call || !event_call->event.funcs ||
2947 !event_call->event.funcs->trace)
2948 return;
2949
2950 file = fbuffer->trace_file;
2951 if (test_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags) ||
2952 (unlikely(file->flags & EVENT_FILE_FL_FILTERED) &&
2953 !filter_match_preds(file->filter, fbuffer->entry)))
2954 return;
2955
2956 event = &fbuffer->trace_file->event_call->event;
2957
2958 raw_spin_lock_irqsave(&tracepoint_iter_lock, flags);
2959 trace_seq_init(&iter->seq);
2960 iter->ent = fbuffer->entry;
2961 event_call->event.funcs->trace(iter, 0, event);
2962 trace_seq_putc(&iter->seq, 0);
2963 printk("%s", iter->seq.buffer);
2964
2965 raw_spin_unlock_irqrestore(&tracepoint_iter_lock, flags);
2966}
2967
2968int tracepoint_printk_sysctl(struct ctl_table *table, int write,
2969 void *buffer, size_t *lenp,
2970 loff_t *ppos)
2971{
2972 int save_tracepoint_printk;
2973 int ret;
2974
2975 mutex_lock(&tracepoint_printk_mutex);
2976 save_tracepoint_printk = tracepoint_printk;
2977
2978 ret = proc_dointvec(table, write, buffer, lenp, ppos);
2979
2980 /*
2981 * This will force exiting early, as tracepoint_printk
2982 * is always zero when tracepoint_printk_iter is not allocated
2983 */
2984 if (!tracepoint_print_iter)
2985 tracepoint_printk = 0;
2986
2987 if (save_tracepoint_printk == tracepoint_printk)
2988 goto out;
2989
2990 if (tracepoint_printk)
2991 static_key_enable(&tracepoint_printk_key.key);
2992 else
2993 static_key_disable(&tracepoint_printk_key.key);
2994
2995 out:
2996 mutex_unlock(&tracepoint_printk_mutex);
2997
2998 return ret;
2999}
3000
3001void trace_event_buffer_commit(struct trace_event_buffer *fbuffer)
3002{
3003 enum event_trigger_type tt = ETT_NONE;
3004 struct trace_event_file *file = fbuffer->trace_file;
3005
3006 if (__event_trigger_test_discard(file, fbuffer->buffer, fbuffer->event,
3007 fbuffer->entry, &tt))
3008 goto discard;
3009
3010 if (static_key_false(&tracepoint_printk_key.key))
3011 output_printk(fbuffer);
3012
3013 if (static_branch_unlikely(&trace_event_exports_enabled))
3014 ftrace_exports(fbuffer->event, TRACE_EXPORT_EVENT);
3015
3016 trace_buffer_unlock_commit_regs(file->tr, fbuffer->buffer,
3017 fbuffer->event, fbuffer->trace_ctx, fbuffer->regs);
3018
3019discard:
3020 if (tt)
3021 event_triggers_post_call(file, tt);
3022
3023}
3024EXPORT_SYMBOL_GPL(trace_event_buffer_commit);
3025
3026/*
3027 * Skip 3:
3028 *
3029 * trace_buffer_unlock_commit_regs()
3030 * trace_event_buffer_commit()
3031 * trace_event_raw_event_xxx()
3032 */
3033# define STACK_SKIP 3
3034
3035void trace_buffer_unlock_commit_regs(struct trace_array *tr,
3036 struct trace_buffer *buffer,
3037 struct ring_buffer_event *event,
3038 unsigned int trace_ctx,
3039 struct pt_regs *regs)
3040{
3041 __buffer_unlock_commit(buffer, event);
3042
3043 /*
3044 * If regs is not set, then skip the necessary functions.
3045 * Note, we can still get here via blktrace, wakeup tracer
3046 * and mmiotrace, but that's ok if they lose a function or
3047 * two. They are not that meaningful.
3048 */
3049 ftrace_trace_stack(tr, buffer, trace_ctx, regs ? 0 : STACK_SKIP, regs);
3050 ftrace_trace_userstack(tr, buffer, trace_ctx);
3051}
3052
3053/*
3054 * Similar to trace_buffer_unlock_commit_regs() but do not dump stack.
3055 */
3056void
3057trace_buffer_unlock_commit_nostack(struct trace_buffer *buffer,
3058 struct ring_buffer_event *event)
3059{
3060 __buffer_unlock_commit(buffer, event);
3061}
3062
3063void
3064trace_function(struct trace_array *tr, unsigned long ip, unsigned long
3065 parent_ip, unsigned int trace_ctx)
3066{
3067 struct trace_event_call *call = &event_function;
3068 struct trace_buffer *buffer = tr->array_buffer.buffer;
3069 struct ring_buffer_event *event;
3070 struct ftrace_entry *entry;
3071
3072 event = __trace_buffer_lock_reserve(buffer, TRACE_FN, sizeof(*entry),
3073 trace_ctx);
3074 if (!event)
3075 return;
3076 entry = ring_buffer_event_data(event);
3077 entry->ip = ip;
3078 entry->parent_ip = parent_ip;
3079
3080 if (!call_filter_check_discard(call, entry, buffer, event)) {
3081 if (static_branch_unlikely(&trace_function_exports_enabled))
3082 ftrace_exports(event, TRACE_EXPORT_FUNCTION);
3083 __buffer_unlock_commit(buffer, event);
3084 }
3085}
3086
3087#ifdef CONFIG_STACKTRACE
3088
3089/* Allow 4 levels of nesting: normal, softirq, irq, NMI */
3090#define FTRACE_KSTACK_NESTING 4
3091
3092#define FTRACE_KSTACK_ENTRIES (PAGE_SIZE / FTRACE_KSTACK_NESTING)
3093
3094struct ftrace_stack {
3095 unsigned long calls[FTRACE_KSTACK_ENTRIES];
3096};
3097
3098
3099struct ftrace_stacks {
3100 struct ftrace_stack stacks[FTRACE_KSTACK_NESTING];
3101};
3102
3103static DEFINE_PER_CPU(struct ftrace_stacks, ftrace_stacks);
3104static DEFINE_PER_CPU(int, ftrace_stack_reserve);
3105
3106static void __ftrace_trace_stack(struct trace_buffer *buffer,
3107 unsigned int trace_ctx,
3108 int skip, struct pt_regs *regs)
3109{
3110 struct trace_event_call *call = &event_kernel_stack;
3111 struct ring_buffer_event *event;
3112 unsigned int size, nr_entries;
3113 struct ftrace_stack *fstack;
3114 struct stack_entry *entry;
3115 int stackidx;
3116
3117 /*
3118 * Add one, for this function and the call to save_stack_trace()
3119 * If regs is set, then these functions will not be in the way.
3120 */
3121#ifndef CONFIG_UNWINDER_ORC
3122 if (!regs)
3123 skip++;
3124#endif
3125
3126 preempt_disable_notrace();
3127
3128 stackidx = __this_cpu_inc_return(ftrace_stack_reserve) - 1;
3129
3130 /* This should never happen. If it does, yell once and skip */
3131 if (WARN_ON_ONCE(stackidx >= FTRACE_KSTACK_NESTING))
3132 goto out;
3133
3134 /*
3135 * The above __this_cpu_inc_return() is 'atomic' cpu local. An
3136 * interrupt will either see the value pre increment or post
3137 * increment. If the interrupt happens pre increment it will have
3138 * restored the counter when it returns. We just need a barrier to
3139 * keep gcc from moving things around.
3140 */
3141 barrier();
3142
3143 fstack = this_cpu_ptr(ftrace_stacks.stacks) + stackidx;
3144 size = ARRAY_SIZE(fstack->calls);
3145
3146 if (regs) {
3147 nr_entries = stack_trace_save_regs(regs, fstack->calls,
3148 size, skip);
3149 } else {
3150 nr_entries = stack_trace_save(fstack->calls, size, skip);
3151 }
3152
3153 event = __trace_buffer_lock_reserve(buffer, TRACE_STACK,
3154 struct_size(entry, caller, nr_entries),
3155 trace_ctx);
3156 if (!event)
3157 goto out;
3158 entry = ring_buffer_event_data(event);
3159
3160 entry->size = nr_entries;
3161 memcpy(&entry->caller, fstack->calls,
3162 flex_array_size(entry, caller, nr_entries));
3163
3164 if (!call_filter_check_discard(call, entry, buffer, event))
3165 __buffer_unlock_commit(buffer, event);
3166
3167 out:
3168 /* Again, don't let gcc optimize things here */
3169 barrier();
3170 __this_cpu_dec(ftrace_stack_reserve);
3171 preempt_enable_notrace();
3172
3173}
3174
3175static inline void ftrace_trace_stack(struct trace_array *tr,
3176 struct trace_buffer *buffer,
3177 unsigned int trace_ctx,
3178 int skip, struct pt_regs *regs)
3179{
3180 if (!(tr->trace_flags & TRACE_ITER_STACKTRACE))
3181 return;
3182
3183 __ftrace_trace_stack(buffer, trace_ctx, skip, regs);
3184}
3185
3186void __trace_stack(struct trace_array *tr, unsigned int trace_ctx,
3187 int skip)
3188{
3189 struct trace_buffer *buffer = tr->array_buffer.buffer;
3190
3191 if (rcu_is_watching()) {
3192 __ftrace_trace_stack(buffer, trace_ctx, skip, NULL);
3193 return;
3194 }
3195
3196 if (WARN_ON_ONCE(IS_ENABLED(CONFIG_GENERIC_ENTRY)))
3197 return;
3198
3199 /*
3200 * When an NMI triggers, RCU is enabled via ct_nmi_enter(),
3201 * but if the above rcu_is_watching() failed, then the NMI
3202 * triggered someplace critical, and ct_irq_enter() should
3203 * not be called from NMI.
3204 */
3205 if (unlikely(in_nmi()))
3206 return;
3207
3208 ct_irq_enter_irqson();
3209 __ftrace_trace_stack(buffer, trace_ctx, skip, NULL);
3210 ct_irq_exit_irqson();
3211}
3212
3213/**
3214 * trace_dump_stack - record a stack back trace in the trace buffer
3215 * @skip: Number of functions to skip (helper handlers)
3216 */
3217void trace_dump_stack(int skip)
3218{
3219 if (tracing_disabled || tracing_selftest_running)
3220 return;
3221
3222#ifndef CONFIG_UNWINDER_ORC
3223 /* Skip 1 to skip this function. */
3224 skip++;
3225#endif
3226 __ftrace_trace_stack(global_trace.array_buffer.buffer,
3227 tracing_gen_ctx(), skip, NULL);
3228}
3229EXPORT_SYMBOL_GPL(trace_dump_stack);
3230
3231#ifdef CONFIG_USER_STACKTRACE_SUPPORT
3232static DEFINE_PER_CPU(int, user_stack_count);
3233
3234static void
3235ftrace_trace_userstack(struct trace_array *tr,
3236 struct trace_buffer *buffer, unsigned int trace_ctx)
3237{
3238 struct trace_event_call *call = &event_user_stack;
3239 struct ring_buffer_event *event;
3240 struct userstack_entry *entry;
3241
3242 if (!(tr->trace_flags & TRACE_ITER_USERSTACKTRACE))
3243 return;
3244
3245 /*
3246 * NMIs can not handle page faults, even with fix ups.
3247 * The save user stack can (and often does) fault.
3248 */
3249 if (unlikely(in_nmi()))
3250 return;
3251
3252 /*
3253 * prevent recursion, since the user stack tracing may
3254 * trigger other kernel events.
3255 */
3256 preempt_disable();
3257 if (__this_cpu_read(user_stack_count))
3258 goto out;
3259
3260 __this_cpu_inc(user_stack_count);
3261
3262 event = __trace_buffer_lock_reserve(buffer, TRACE_USER_STACK,
3263 sizeof(*entry), trace_ctx);
3264 if (!event)
3265 goto out_drop_count;
3266 entry = ring_buffer_event_data(event);
3267
3268 entry->tgid = current->tgid;
3269 memset(&entry->caller, 0, sizeof(entry->caller));
3270
3271 stack_trace_save_user(entry->caller, FTRACE_STACK_ENTRIES);
3272 if (!call_filter_check_discard(call, entry, buffer, event))
3273 __buffer_unlock_commit(buffer, event);
3274
3275 out_drop_count:
3276 __this_cpu_dec(user_stack_count);
3277 out:
3278 preempt_enable();
3279}
3280#else /* CONFIG_USER_STACKTRACE_SUPPORT */
3281static void ftrace_trace_userstack(struct trace_array *tr,
3282 struct trace_buffer *buffer,
3283 unsigned int trace_ctx)
3284{
3285}
3286#endif /* !CONFIG_USER_STACKTRACE_SUPPORT */
3287
3288#endif /* CONFIG_STACKTRACE */
3289
3290static inline void
3291func_repeats_set_delta_ts(struct func_repeats_entry *entry,
3292 unsigned long long delta)
3293{
3294 entry->bottom_delta_ts = delta & U32_MAX;
3295 entry->top_delta_ts = (delta >> 32);
3296}
3297
3298void trace_last_func_repeats(struct trace_array *tr,
3299 struct trace_func_repeats *last_info,
3300 unsigned int trace_ctx)
3301{
3302 struct trace_buffer *buffer = tr->array_buffer.buffer;
3303 struct func_repeats_entry *entry;
3304 struct ring_buffer_event *event;
3305 u64 delta;
3306
3307 event = __trace_buffer_lock_reserve(buffer, TRACE_FUNC_REPEATS,
3308 sizeof(*entry), trace_ctx);
3309 if (!event)
3310 return;
3311
3312 delta = ring_buffer_event_time_stamp(buffer, event) -
3313 last_info->ts_last_call;
3314
3315 entry = ring_buffer_event_data(event);
3316 entry->ip = last_info->ip;
3317 entry->parent_ip = last_info->parent_ip;
3318 entry->count = last_info->count;
3319 func_repeats_set_delta_ts(entry, delta);
3320
3321 __buffer_unlock_commit(buffer, event);
3322}
3323
3324/* created for use with alloc_percpu */
3325struct trace_buffer_struct {
3326 int nesting;
3327 char buffer[4][TRACE_BUF_SIZE];
3328};
3329
3330static struct trace_buffer_struct __percpu *trace_percpu_buffer;
3331
3332/*
3333 * This allows for lockless recording. If we're nested too deeply, then
3334 * this returns NULL.
3335 */
3336static char *get_trace_buf(void)
3337{
3338 struct trace_buffer_struct *buffer = this_cpu_ptr(trace_percpu_buffer);
3339
3340 if (!trace_percpu_buffer || buffer->nesting >= 4)
3341 return NULL;
3342
3343 buffer->nesting++;
3344
3345 /* Interrupts must see nesting incremented before we use the buffer */
3346 barrier();
3347 return &buffer->buffer[buffer->nesting - 1][0];
3348}
3349
3350static void put_trace_buf(void)
3351{
3352 /* Don't let the decrement of nesting leak before this */
3353 barrier();
3354 this_cpu_dec(trace_percpu_buffer->nesting);
3355}
3356
3357static int alloc_percpu_trace_buffer(void)
3358{
3359 struct trace_buffer_struct __percpu *buffers;
3360
3361 if (trace_percpu_buffer)
3362 return 0;
3363
3364 buffers = alloc_percpu(struct trace_buffer_struct);
3365 if (MEM_FAIL(!buffers, "Could not allocate percpu trace_printk buffer"))
3366 return -ENOMEM;
3367
3368 trace_percpu_buffer = buffers;
3369 return 0;
3370}
3371
3372static int buffers_allocated;
3373
3374void trace_printk_init_buffers(void)
3375{
3376 if (buffers_allocated)
3377 return;
3378
3379 if (alloc_percpu_trace_buffer())
3380 return;
3381
3382 /* trace_printk() is for debug use only. Don't use it in production. */
3383
3384 pr_warn("\n");
3385 pr_warn("**********************************************************\n");
3386 pr_warn("** NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE **\n");
3387 pr_warn("** **\n");
3388 pr_warn("** trace_printk() being used. Allocating extra memory. **\n");
3389 pr_warn("** **\n");
3390 pr_warn("** This means that this is a DEBUG kernel and it is **\n");
3391 pr_warn("** unsafe for production use. **\n");
3392 pr_warn("** **\n");
3393 pr_warn("** If you see this message and you are not debugging **\n");
3394 pr_warn("** the kernel, report this immediately to your vendor! **\n");
3395 pr_warn("** **\n");
3396 pr_warn("** NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE **\n");
3397 pr_warn("**********************************************************\n");
3398
3399 /* Expand the buffers to set size */
3400 tracing_update_buffers(&global_trace);
3401
3402 buffers_allocated = 1;
3403
3404 /*
3405 * trace_printk_init_buffers() can be called by modules.
3406 * If that happens, then we need to start cmdline recording
3407 * directly here. If the global_trace.buffer is already
3408 * allocated here, then this was called by module code.
3409 */
3410 if (global_trace.array_buffer.buffer)
3411 tracing_start_cmdline_record();
3412}
3413EXPORT_SYMBOL_GPL(trace_printk_init_buffers);
3414
3415void trace_printk_start_comm(void)
3416{
3417 /* Start tracing comms if trace printk is set */
3418 if (!buffers_allocated)
3419 return;
3420 tracing_start_cmdline_record();
3421}
3422
3423static void trace_printk_start_stop_comm(int enabled)
3424{
3425 if (!buffers_allocated)
3426 return;
3427
3428 if (enabled)
3429 tracing_start_cmdline_record();
3430 else
3431 tracing_stop_cmdline_record();
3432}
3433
3434/**
3435 * trace_vbprintk - write binary msg to tracing buffer
3436 * @ip: The address of the caller
3437 * @fmt: The string format to write to the buffer
3438 * @args: Arguments for @fmt
3439 */
3440int trace_vbprintk(unsigned long ip, const char *fmt, va_list args)
3441{
3442 struct trace_event_call *call = &event_bprint;
3443 struct ring_buffer_event *event;
3444 struct trace_buffer *buffer;
3445 struct trace_array *tr = &global_trace;
3446 struct bprint_entry *entry;
3447 unsigned int trace_ctx;
3448 char *tbuffer;
3449 int len = 0, size;
3450
3451 if (unlikely(tracing_selftest_running || tracing_disabled))
3452 return 0;
3453
3454 /* Don't pollute graph traces with trace_vprintk internals */
3455 pause_graph_tracing();
3456
3457 trace_ctx = tracing_gen_ctx();
3458 preempt_disable_notrace();
3459
3460 tbuffer = get_trace_buf();
3461 if (!tbuffer) {
3462 len = 0;
3463 goto out_nobuffer;
3464 }
3465
3466 len = vbin_printf((u32 *)tbuffer, TRACE_BUF_SIZE/sizeof(int), fmt, args);
3467
3468 if (len > TRACE_BUF_SIZE/sizeof(int) || len < 0)
3469 goto out_put;
3470
3471 size = sizeof(*entry) + sizeof(u32) * len;
3472 buffer = tr->array_buffer.buffer;
3473 ring_buffer_nest_start(buffer);
3474 event = __trace_buffer_lock_reserve(buffer, TRACE_BPRINT, size,
3475 trace_ctx);
3476 if (!event)
3477 goto out;
3478 entry = ring_buffer_event_data(event);
3479 entry->ip = ip;
3480 entry->fmt = fmt;
3481
3482 memcpy(entry->buf, tbuffer, sizeof(u32) * len);
3483 if (!call_filter_check_discard(call, entry, buffer, event)) {
3484 __buffer_unlock_commit(buffer, event);
3485 ftrace_trace_stack(tr, buffer, trace_ctx, 6, NULL);
3486 }
3487
3488out:
3489 ring_buffer_nest_end(buffer);
3490out_put:
3491 put_trace_buf();
3492
3493out_nobuffer:
3494 preempt_enable_notrace();
3495 unpause_graph_tracing();
3496
3497 return len;
3498}
3499EXPORT_SYMBOL_GPL(trace_vbprintk);
3500
3501__printf(3, 0)
3502static int
3503__trace_array_vprintk(struct trace_buffer *buffer,
3504 unsigned long ip, const char *fmt, va_list args)
3505{
3506 struct trace_event_call *call = &event_print;
3507 struct ring_buffer_event *event;
3508 int len = 0, size;
3509 struct print_entry *entry;
3510 unsigned int trace_ctx;
3511 char *tbuffer;
3512
3513 if (tracing_disabled)
3514 return 0;
3515
3516 /* Don't pollute graph traces with trace_vprintk internals */
3517 pause_graph_tracing();
3518
3519 trace_ctx = tracing_gen_ctx();
3520 preempt_disable_notrace();
3521
3522
3523 tbuffer = get_trace_buf();
3524 if (!tbuffer) {
3525 len = 0;
3526 goto out_nobuffer;
3527 }
3528
3529 len = vscnprintf(tbuffer, TRACE_BUF_SIZE, fmt, args);
3530
3531 size = sizeof(*entry) + len + 1;
3532 ring_buffer_nest_start(buffer);
3533 event = __trace_buffer_lock_reserve(buffer, TRACE_PRINT, size,
3534 trace_ctx);
3535 if (!event)
3536 goto out;
3537 entry = ring_buffer_event_data(event);
3538 entry->ip = ip;
3539
3540 memcpy(&entry->buf, tbuffer, len + 1);
3541 if (!call_filter_check_discard(call, entry, buffer, event)) {
3542 __buffer_unlock_commit(buffer, event);
3543 ftrace_trace_stack(&global_trace, buffer, trace_ctx, 6, NULL);
3544 }
3545
3546out:
3547 ring_buffer_nest_end(buffer);
3548 put_trace_buf();
3549
3550out_nobuffer:
3551 preempt_enable_notrace();
3552 unpause_graph_tracing();
3553
3554 return len;
3555}
3556
3557__printf(3, 0)
3558int trace_array_vprintk(struct trace_array *tr,
3559 unsigned long ip, const char *fmt, va_list args)
3560{
3561 if (tracing_selftest_running && tr == &global_trace)
3562 return 0;
3563
3564 return __trace_array_vprintk(tr->array_buffer.buffer, ip, fmt, args);
3565}
3566
3567/**
3568 * trace_array_printk - Print a message to a specific instance
3569 * @tr: The instance trace_array descriptor
3570 * @ip: The instruction pointer that this is called from.
3571 * @fmt: The format to print (printf format)
3572 *
3573 * If a subsystem sets up its own instance, they have the right to
3574 * printk strings into their tracing instance buffer using this
3575 * function. Note, this function will not write into the top level
3576 * buffer (use trace_printk() for that), as writing into the top level
3577 * buffer should only have events that can be individually disabled.
3578 * trace_printk() is only used for debugging a kernel, and should not
3579 * be ever incorporated in normal use.
3580 *
3581 * trace_array_printk() can be used, as it will not add noise to the
3582 * top level tracing buffer.
3583 *
3584 * Note, trace_array_init_printk() must be called on @tr before this
3585 * can be used.
3586 */
3587__printf(3, 0)
3588int trace_array_printk(struct trace_array *tr,
3589 unsigned long ip, const char *fmt, ...)
3590{
3591 int ret;
3592 va_list ap;
3593
3594 if (!tr)
3595 return -ENOENT;
3596
3597 /* This is only allowed for created instances */
3598 if (tr == &global_trace)
3599 return 0;
3600
3601 if (!(tr->trace_flags & TRACE_ITER_PRINTK))
3602 return 0;
3603
3604 va_start(ap, fmt);
3605 ret = trace_array_vprintk(tr, ip, fmt, ap);
3606 va_end(ap);
3607 return ret;
3608}
3609EXPORT_SYMBOL_GPL(trace_array_printk);
3610
3611/**
3612 * trace_array_init_printk - Initialize buffers for trace_array_printk()
3613 * @tr: The trace array to initialize the buffers for
3614 *
3615 * As trace_array_printk() only writes into instances, they are OK to
3616 * have in the kernel (unlike trace_printk()). This needs to be called
3617 * before trace_array_printk() can be used on a trace_array.
3618 */
3619int trace_array_init_printk(struct trace_array *tr)
3620{
3621 if (!tr)
3622 return -ENOENT;
3623
3624 /* This is only allowed for created instances */
3625 if (tr == &global_trace)
3626 return -EINVAL;
3627
3628 return alloc_percpu_trace_buffer();
3629}
3630EXPORT_SYMBOL_GPL(trace_array_init_printk);
3631
3632__printf(3, 4)
3633int trace_array_printk_buf(struct trace_buffer *buffer,
3634 unsigned long ip, const char *fmt, ...)
3635{
3636 int ret;
3637 va_list ap;
3638
3639 if (!(global_trace.trace_flags & TRACE_ITER_PRINTK))
3640 return 0;
3641
3642 va_start(ap, fmt);
3643 ret = __trace_array_vprintk(buffer, ip, fmt, ap);
3644 va_end(ap);
3645 return ret;
3646}
3647
3648__printf(2, 0)
3649int trace_vprintk(unsigned long ip, const char *fmt, va_list args)
3650{
3651 return trace_array_vprintk(&global_trace, ip, fmt, args);
3652}
3653EXPORT_SYMBOL_GPL(trace_vprintk);
3654
3655static void trace_iterator_increment(struct trace_iterator *iter)
3656{
3657 struct ring_buffer_iter *buf_iter = trace_buffer_iter(iter, iter->cpu);
3658
3659 iter->idx++;
3660 if (buf_iter)
3661 ring_buffer_iter_advance(buf_iter);
3662}
3663
3664static struct trace_entry *
3665peek_next_entry(struct trace_iterator *iter, int cpu, u64 *ts,
3666 unsigned long *lost_events)
3667{
3668 struct ring_buffer_event *event;
3669 struct ring_buffer_iter *buf_iter = trace_buffer_iter(iter, cpu);
3670
3671 if (buf_iter) {
3672 event = ring_buffer_iter_peek(buf_iter, ts);
3673 if (lost_events)
3674 *lost_events = ring_buffer_iter_dropped(buf_iter) ?
3675 (unsigned long)-1 : 0;
3676 } else {
3677 event = ring_buffer_peek(iter->array_buffer->buffer, cpu, ts,
3678 lost_events);
3679 }
3680
3681 if (event) {
3682 iter->ent_size = ring_buffer_event_length(event);
3683 return ring_buffer_event_data(event);
3684 }
3685 iter->ent_size = 0;
3686 return NULL;
3687}
3688
3689static struct trace_entry *
3690__find_next_entry(struct trace_iterator *iter, int *ent_cpu,
3691 unsigned long *missing_events, u64 *ent_ts)
3692{
3693 struct trace_buffer *buffer = iter->array_buffer->buffer;
3694 struct trace_entry *ent, *next = NULL;
3695 unsigned long lost_events = 0, next_lost = 0;
3696 int cpu_file = iter->cpu_file;
3697 u64 next_ts = 0, ts;
3698 int next_cpu = -1;
3699 int next_size = 0;
3700 int cpu;
3701
3702 /*
3703 * If we are in a per_cpu trace file, don't bother by iterating over
3704 * all cpu and peek directly.
3705 */
3706 if (cpu_file > RING_BUFFER_ALL_CPUS) {
3707 if (ring_buffer_empty_cpu(buffer, cpu_file))
3708 return NULL;
3709 ent = peek_next_entry(iter, cpu_file, ent_ts, missing_events);
3710 if (ent_cpu)
3711 *ent_cpu = cpu_file;
3712
3713 return ent;
3714 }
3715
3716 for_each_tracing_cpu(cpu) {
3717
3718 if (ring_buffer_empty_cpu(buffer, cpu))
3719 continue;
3720
3721 ent = peek_next_entry(iter, cpu, &ts, &lost_events);
3722
3723 /*
3724 * Pick the entry with the smallest timestamp:
3725 */
3726 if (ent && (!next || ts < next_ts)) {
3727 next = ent;
3728 next_cpu = cpu;
3729 next_ts = ts;
3730 next_lost = lost_events;
3731 next_size = iter->ent_size;
3732 }
3733 }
3734
3735 iter->ent_size = next_size;
3736
3737 if (ent_cpu)
3738 *ent_cpu = next_cpu;
3739
3740 if (ent_ts)
3741 *ent_ts = next_ts;
3742
3743 if (missing_events)
3744 *missing_events = next_lost;
3745
3746 return next;
3747}
3748
3749#define STATIC_FMT_BUF_SIZE 128
3750static char static_fmt_buf[STATIC_FMT_BUF_SIZE];
3751
3752char *trace_iter_expand_format(struct trace_iterator *iter)
3753{
3754 char *tmp;
3755
3756 /*
3757 * iter->tr is NULL when used with tp_printk, which makes
3758 * this get called where it is not safe to call krealloc().
3759 */
3760 if (!iter->tr || iter->fmt == static_fmt_buf)
3761 return NULL;
3762
3763 tmp = krealloc(iter->fmt, iter->fmt_size + STATIC_FMT_BUF_SIZE,
3764 GFP_KERNEL);
3765 if (tmp) {
3766 iter->fmt_size += STATIC_FMT_BUF_SIZE;
3767 iter->fmt = tmp;
3768 }
3769
3770 return tmp;
3771}
3772
3773/* Returns true if the string is safe to dereference from an event */
3774static bool trace_safe_str(struct trace_iterator *iter, const char *str,
3775 bool star, int len)
3776{
3777 unsigned long addr = (unsigned long)str;
3778 struct trace_event *trace_event;
3779 struct trace_event_call *event;
3780
3781 /* Ignore strings with no length */
3782 if (star && !len)
3783 return true;
3784
3785 /* OK if part of the event data */
3786 if ((addr >= (unsigned long)iter->ent) &&
3787 (addr < (unsigned long)iter->ent + iter->ent_size))
3788 return true;
3789
3790 /* OK if part of the temp seq buffer */
3791 if ((addr >= (unsigned long)iter->tmp_seq.buffer) &&
3792 (addr < (unsigned long)iter->tmp_seq.buffer + TRACE_SEQ_BUFFER_SIZE))
3793 return true;
3794
3795 /* Core rodata can not be freed */
3796 if (is_kernel_rodata(addr))
3797 return true;
3798
3799 if (trace_is_tracepoint_string(str))
3800 return true;
3801
3802 /*
3803 * Now this could be a module event, referencing core module
3804 * data, which is OK.
3805 */
3806 if (!iter->ent)
3807 return false;
3808
3809 trace_event = ftrace_find_event(iter->ent->type);
3810 if (!trace_event)
3811 return false;
3812
3813 event = container_of(trace_event, struct trace_event_call, event);
3814 if ((event->flags & TRACE_EVENT_FL_DYNAMIC) || !event->module)
3815 return false;
3816
3817 /* Would rather have rodata, but this will suffice */
3818 if (within_module_core(addr, event->module))
3819 return true;
3820
3821 return false;
3822}
3823
3824static DEFINE_STATIC_KEY_FALSE(trace_no_verify);
3825
3826static int test_can_verify_check(const char *fmt, ...)
3827{
3828 char buf[16];
3829 va_list ap;
3830 int ret;
3831
3832 /*
3833 * The verifier is dependent on vsnprintf() modifies the va_list
3834 * passed to it, where it is sent as a reference. Some architectures
3835 * (like x86_32) passes it by value, which means that vsnprintf()
3836 * does not modify the va_list passed to it, and the verifier
3837 * would then need to be able to understand all the values that
3838 * vsnprintf can use. If it is passed by value, then the verifier
3839 * is disabled.
3840 */
3841 va_start(ap, fmt);
3842 vsnprintf(buf, 16, "%d", ap);
3843 ret = va_arg(ap, int);
3844 va_end(ap);
3845
3846 return ret;
3847}
3848
3849static void test_can_verify(void)
3850{
3851 if (!test_can_verify_check("%d %d", 0, 1)) {
3852 pr_info("trace event string verifier disabled\n");
3853 static_branch_inc(&trace_no_verify);
3854 }
3855}
3856
3857/**
3858 * trace_check_vprintf - Check dereferenced strings while writing to the seq buffer
3859 * @iter: The iterator that holds the seq buffer and the event being printed
3860 * @fmt: The format used to print the event
3861 * @ap: The va_list holding the data to print from @fmt.
3862 *
3863 * This writes the data into the @iter->seq buffer using the data from
3864 * @fmt and @ap. If the format has a %s, then the source of the string
3865 * is examined to make sure it is safe to print, otherwise it will
3866 * warn and print "[UNSAFE MEMORY]" in place of the dereferenced string
3867 * pointer.
3868 */
3869void trace_check_vprintf(struct trace_iterator *iter, const char *fmt,
3870 va_list ap)
3871{
3872 const char *p = fmt;
3873 const char *str;
3874 int i, j;
3875
3876 if (WARN_ON_ONCE(!fmt))
3877 return;
3878
3879 if (static_branch_unlikely(&trace_no_verify))
3880 goto print;
3881
3882 /* Don't bother checking when doing a ftrace_dump() */
3883 if (iter->fmt == static_fmt_buf)
3884 goto print;
3885
3886 while (*p) {
3887 bool star = false;
3888 int len = 0;
3889
3890 j = 0;
3891
3892 /* We only care about %s and variants */
3893 for (i = 0; p[i]; i++) {
3894 if (i + 1 >= iter->fmt_size) {
3895 /*
3896 * If we can't expand the copy buffer,
3897 * just print it.
3898 */
3899 if (!trace_iter_expand_format(iter))
3900 goto print;
3901 }
3902
3903 if (p[i] == '\\' && p[i+1]) {
3904 i++;
3905 continue;
3906 }
3907 if (p[i] == '%') {
3908 /* Need to test cases like %08.*s */
3909 for (j = 1; p[i+j]; j++) {
3910 if (isdigit(p[i+j]) ||
3911 p[i+j] == '.')
3912 continue;
3913 if (p[i+j] == '*') {
3914 star = true;
3915 continue;
3916 }
3917 break;
3918 }
3919 if (p[i+j] == 's')
3920 break;
3921 star = false;
3922 }
3923 j = 0;
3924 }
3925 /* If no %s found then just print normally */
3926 if (!p[i])
3927 break;
3928
3929 /* Copy up to the %s, and print that */
3930 strncpy(iter->fmt, p, i);
3931 iter->fmt[i] = '\0';
3932 trace_seq_vprintf(&iter->seq, iter->fmt, ap);
3933
3934 /*
3935 * If iter->seq is full, the above call no longer guarantees
3936 * that ap is in sync with fmt processing, and further calls
3937 * to va_arg() can return wrong positional arguments.
3938 *
3939 * Ensure that ap is no longer used in this case.
3940 */
3941 if (iter->seq.full) {
3942 p = "";
3943 break;
3944 }
3945
3946 if (star)
3947 len = va_arg(ap, int);
3948
3949 /* The ap now points to the string data of the %s */
3950 str = va_arg(ap, const char *);
3951
3952 /*
3953 * If you hit this warning, it is likely that the
3954 * trace event in question used %s on a string that
3955 * was saved at the time of the event, but may not be
3956 * around when the trace is read. Use __string(),
3957 * __assign_str() and __get_str() helpers in the TRACE_EVENT()
3958 * instead. See samples/trace_events/trace-events-sample.h
3959 * for reference.
3960 */
3961 if (WARN_ONCE(!trace_safe_str(iter, str, star, len),
3962 "fmt: '%s' current_buffer: '%s'",
3963 fmt, seq_buf_str(&iter->seq.seq))) {
3964 int ret;
3965
3966 /* Try to safely read the string */
3967 if (star) {
3968 if (len + 1 > iter->fmt_size)
3969 len = iter->fmt_size - 1;
3970 if (len < 0)
3971 len = 0;
3972 ret = copy_from_kernel_nofault(iter->fmt, str, len);
3973 iter->fmt[len] = 0;
3974 star = false;
3975 } else {
3976 ret = strncpy_from_kernel_nofault(iter->fmt, str,
3977 iter->fmt_size);
3978 }
3979 if (ret < 0)
3980 trace_seq_printf(&iter->seq, "(0x%px)", str);
3981 else
3982 trace_seq_printf(&iter->seq, "(0x%px:%s)",
3983 str, iter->fmt);
3984 str = "[UNSAFE-MEMORY]";
3985 strcpy(iter->fmt, "%s");
3986 } else {
3987 strncpy(iter->fmt, p + i, j + 1);
3988 iter->fmt[j+1] = '\0';
3989 }
3990 if (star)
3991 trace_seq_printf(&iter->seq, iter->fmt, len, str);
3992 else
3993 trace_seq_printf(&iter->seq, iter->fmt, str);
3994
3995 p += i + j + 1;
3996 }
3997 print:
3998 if (*p)
3999 trace_seq_vprintf(&iter->seq, p, ap);
4000}
4001
4002const char *trace_event_format(struct trace_iterator *iter, const char *fmt)
4003{
4004 const char *p, *new_fmt;
4005 char *q;
4006
4007 if (WARN_ON_ONCE(!fmt))
4008 return fmt;
4009
4010 if (!iter->tr || iter->tr->trace_flags & TRACE_ITER_HASH_PTR)
4011 return fmt;
4012
4013 p = fmt;
4014 new_fmt = q = iter->fmt;
4015 while (*p) {
4016 if (unlikely(q - new_fmt + 3 > iter->fmt_size)) {
4017 if (!trace_iter_expand_format(iter))
4018 return fmt;
4019
4020 q += iter->fmt - new_fmt;
4021 new_fmt = iter->fmt;
4022 }
4023
4024 *q++ = *p++;
4025
4026 /* Replace %p with %px */
4027 if (p[-1] == '%') {
4028 if (p[0] == '%') {
4029 *q++ = *p++;
4030 } else if (p[0] == 'p' && !isalnum(p[1])) {
4031 *q++ = *p++;
4032 *q++ = 'x';
4033 }
4034 }
4035 }
4036 *q = '\0';
4037
4038 return new_fmt;
4039}
4040
4041#define STATIC_TEMP_BUF_SIZE 128
4042static char static_temp_buf[STATIC_TEMP_BUF_SIZE] __aligned(4);
4043
4044/* Find the next real entry, without updating the iterator itself */
4045struct trace_entry *trace_find_next_entry(struct trace_iterator *iter,
4046 int *ent_cpu, u64 *ent_ts)
4047{
4048 /* __find_next_entry will reset ent_size */
4049 int ent_size = iter->ent_size;
4050 struct trace_entry *entry;
4051
4052 /*
4053 * If called from ftrace_dump(), then the iter->temp buffer
4054 * will be the static_temp_buf and not created from kmalloc.
4055 * If the entry size is greater than the buffer, we can
4056 * not save it. Just return NULL in that case. This is only
4057 * used to add markers when two consecutive events' time
4058 * stamps have a large delta. See trace_print_lat_context()
4059 */
4060 if (iter->temp == static_temp_buf &&
4061 STATIC_TEMP_BUF_SIZE < ent_size)
4062 return NULL;
4063
4064 /*
4065 * The __find_next_entry() may call peek_next_entry(), which may
4066 * call ring_buffer_peek() that may make the contents of iter->ent
4067 * undefined. Need to copy iter->ent now.
4068 */
4069 if (iter->ent && iter->ent != iter->temp) {
4070 if ((!iter->temp || iter->temp_size < iter->ent_size) &&
4071 !WARN_ON_ONCE(iter->temp == static_temp_buf)) {
4072 void *temp;
4073 temp = kmalloc(iter->ent_size, GFP_KERNEL);
4074 if (!temp)
4075 return NULL;
4076 kfree(iter->temp);
4077 iter->temp = temp;
4078 iter->temp_size = iter->ent_size;
4079 }
4080 memcpy(iter->temp, iter->ent, iter->ent_size);
4081 iter->ent = iter->temp;
4082 }
4083 entry = __find_next_entry(iter, ent_cpu, NULL, ent_ts);
4084 /* Put back the original ent_size */
4085 iter->ent_size = ent_size;
4086
4087 return entry;
4088}
4089
4090/* Find the next real entry, and increment the iterator to the next entry */
4091void *trace_find_next_entry_inc(struct trace_iterator *iter)
4092{
4093 iter->ent = __find_next_entry(iter, &iter->cpu,
4094 &iter->lost_events, &iter->ts);
4095
4096 if (iter->ent)
4097 trace_iterator_increment(iter);
4098
4099 return iter->ent ? iter : NULL;
4100}
4101
4102static void trace_consume(struct trace_iterator *iter)
4103{
4104 ring_buffer_consume(iter->array_buffer->buffer, iter->cpu, &iter->ts,
4105 &iter->lost_events);
4106}
4107
4108static void *s_next(struct seq_file *m, void *v, loff_t *pos)
4109{
4110 struct trace_iterator *iter = m->private;
4111 int i = (int)*pos;
4112 void *ent;
4113
4114 WARN_ON_ONCE(iter->leftover);
4115
4116 (*pos)++;
4117
4118 /* can't go backwards */
4119 if (iter->idx > i)
4120 return NULL;
4121
4122 if (iter->idx < 0)
4123 ent = trace_find_next_entry_inc(iter);
4124 else
4125 ent = iter;
4126
4127 while (ent && iter->idx < i)
4128 ent = trace_find_next_entry_inc(iter);
4129
4130 iter->pos = *pos;
4131
4132 return ent;
4133}
4134
4135void tracing_iter_reset(struct trace_iterator *iter, int cpu)
4136{
4137 struct ring_buffer_iter *buf_iter;
4138 unsigned long entries = 0;
4139 u64 ts;
4140
4141 per_cpu_ptr(iter->array_buffer->data, cpu)->skipped_entries = 0;
4142
4143 buf_iter = trace_buffer_iter(iter, cpu);
4144 if (!buf_iter)
4145 return;
4146
4147 ring_buffer_iter_reset(buf_iter);
4148
4149 /*
4150 * We could have the case with the max latency tracers
4151 * that a reset never took place on a cpu. This is evident
4152 * by the timestamp being before the start of the buffer.
4153 */
4154 while (ring_buffer_iter_peek(buf_iter, &ts)) {
4155 if (ts >= iter->array_buffer->time_start)
4156 break;
4157 entries++;
4158 ring_buffer_iter_advance(buf_iter);
4159 }
4160
4161 per_cpu_ptr(iter->array_buffer->data, cpu)->skipped_entries = entries;
4162}
4163
4164/*
4165 * The current tracer is copied to avoid a global locking
4166 * all around.
4167 */
4168static void *s_start(struct seq_file *m, loff_t *pos)
4169{
4170 struct trace_iterator *iter = m->private;
4171 struct trace_array *tr = iter->tr;
4172 int cpu_file = iter->cpu_file;
4173 void *p = NULL;
4174 loff_t l = 0;
4175 int cpu;
4176
4177 mutex_lock(&trace_types_lock);
4178 if (unlikely(tr->current_trace != iter->trace)) {
4179 /* Close iter->trace before switching to the new current tracer */
4180 if (iter->trace->close)
4181 iter->trace->close(iter);
4182 iter->trace = tr->current_trace;
4183 /* Reopen the new current tracer */
4184 if (iter->trace->open)
4185 iter->trace->open(iter);
4186 }
4187 mutex_unlock(&trace_types_lock);
4188
4189#ifdef CONFIG_TRACER_MAX_TRACE
4190 if (iter->snapshot && iter->trace->use_max_tr)
4191 return ERR_PTR(-EBUSY);
4192#endif
4193
4194 if (*pos != iter->pos) {
4195 iter->ent = NULL;
4196 iter->cpu = 0;
4197 iter->idx = -1;
4198
4199 if (cpu_file == RING_BUFFER_ALL_CPUS) {
4200 for_each_tracing_cpu(cpu)
4201 tracing_iter_reset(iter, cpu);
4202 } else
4203 tracing_iter_reset(iter, cpu_file);
4204
4205 iter->leftover = 0;
4206 for (p = iter; p && l < *pos; p = s_next(m, p, &l))
4207 ;
4208
4209 } else {
4210 /*
4211 * If we overflowed the seq_file before, then we want
4212 * to just reuse the trace_seq buffer again.
4213 */
4214 if (iter->leftover)
4215 p = iter;
4216 else {
4217 l = *pos - 1;
4218 p = s_next(m, p, &l);
4219 }
4220 }
4221
4222 trace_event_read_lock();
4223 trace_access_lock(cpu_file);
4224 return p;
4225}
4226
4227static void s_stop(struct seq_file *m, void *p)
4228{
4229 struct trace_iterator *iter = m->private;
4230
4231#ifdef CONFIG_TRACER_MAX_TRACE
4232 if (iter->snapshot && iter->trace->use_max_tr)
4233 return;
4234#endif
4235
4236 trace_access_unlock(iter->cpu_file);
4237 trace_event_read_unlock();
4238}
4239
4240static void
4241get_total_entries_cpu(struct array_buffer *buf, unsigned long *total,
4242 unsigned long *entries, int cpu)
4243{
4244 unsigned long count;
4245
4246 count = ring_buffer_entries_cpu(buf->buffer, cpu);
4247 /*
4248 * If this buffer has skipped entries, then we hold all
4249 * entries for the trace and we need to ignore the
4250 * ones before the time stamp.
4251 */
4252 if (per_cpu_ptr(buf->data, cpu)->skipped_entries) {
4253 count -= per_cpu_ptr(buf->data, cpu)->skipped_entries;
4254 /* total is the same as the entries */
4255 *total = count;
4256 } else
4257 *total = count +
4258 ring_buffer_overrun_cpu(buf->buffer, cpu);
4259 *entries = count;
4260}
4261
4262static void
4263get_total_entries(struct array_buffer *buf,
4264 unsigned long *total, unsigned long *entries)
4265{
4266 unsigned long t, e;
4267 int cpu;
4268
4269 *total = 0;
4270 *entries = 0;
4271
4272 for_each_tracing_cpu(cpu) {
4273 get_total_entries_cpu(buf, &t, &e, cpu);
4274 *total += t;
4275 *entries += e;
4276 }
4277}
4278
4279unsigned long trace_total_entries_cpu(struct trace_array *tr, int cpu)
4280{
4281 unsigned long total, entries;
4282
4283 if (!tr)
4284 tr = &global_trace;
4285
4286 get_total_entries_cpu(&tr->array_buffer, &total, &entries, cpu);
4287
4288 return entries;
4289}
4290
4291unsigned long trace_total_entries(struct trace_array *tr)
4292{
4293 unsigned long total, entries;
4294
4295 if (!tr)
4296 tr = &global_trace;
4297
4298 get_total_entries(&tr->array_buffer, &total, &entries);
4299
4300 return entries;
4301}
4302
4303static void print_lat_help_header(struct seq_file *m)
4304{
4305 seq_puts(m, "# _------=> CPU# \n"
4306 "# / _-----=> irqs-off/BH-disabled\n"
4307 "# | / _----=> need-resched \n"
4308 "# || / _---=> hardirq/softirq \n"
4309 "# ||| / _--=> preempt-depth \n"
4310 "# |||| / _-=> migrate-disable \n"
4311 "# ||||| / delay \n"
4312 "# cmd pid |||||| time | caller \n"
4313 "# \\ / |||||| \\ | / \n");
4314}
4315
4316static void print_event_info(struct array_buffer *buf, struct seq_file *m)
4317{
4318 unsigned long total;
4319 unsigned long entries;
4320
4321 get_total_entries(buf, &total, &entries);
4322 seq_printf(m, "# entries-in-buffer/entries-written: %lu/%lu #P:%d\n",
4323 entries, total, num_online_cpus());
4324 seq_puts(m, "#\n");
4325}
4326
4327static void print_func_help_header(struct array_buffer *buf, struct seq_file *m,
4328 unsigned int flags)
4329{
4330 bool tgid = flags & TRACE_ITER_RECORD_TGID;
4331
4332 print_event_info(buf, m);
4333
4334 seq_printf(m, "# TASK-PID %s CPU# TIMESTAMP FUNCTION\n", tgid ? " TGID " : "");
4335 seq_printf(m, "# | | %s | | |\n", tgid ? " | " : "");
4336}
4337
4338static void print_func_help_header_irq(struct array_buffer *buf, struct seq_file *m,
4339 unsigned int flags)
4340{
4341 bool tgid = flags & TRACE_ITER_RECORD_TGID;
4342 static const char space[] = " ";
4343 int prec = tgid ? 12 : 2;
4344
4345 print_event_info(buf, m);
4346
4347 seq_printf(m, "# %.*s _-----=> irqs-off/BH-disabled\n", prec, space);
4348 seq_printf(m, "# %.*s / _----=> need-resched\n", prec, space);
4349 seq_printf(m, "# %.*s| / _---=> hardirq/softirq\n", prec, space);
4350 seq_printf(m, "# %.*s|| / _--=> preempt-depth\n", prec, space);
4351 seq_printf(m, "# %.*s||| / _-=> migrate-disable\n", prec, space);
4352 seq_printf(m, "# %.*s|||| / delay\n", prec, space);
4353 seq_printf(m, "# TASK-PID %.*s CPU# ||||| TIMESTAMP FUNCTION\n", prec, " TGID ");
4354 seq_printf(m, "# | | %.*s | ||||| | |\n", prec, " | ");
4355}
4356
4357void
4358print_trace_header(struct seq_file *m, struct trace_iterator *iter)
4359{
4360 unsigned long sym_flags = (global_trace.trace_flags & TRACE_ITER_SYM_MASK);
4361 struct array_buffer *buf = iter->array_buffer;
4362 struct trace_array_cpu *data = per_cpu_ptr(buf->data, buf->cpu);
4363 struct tracer *type = iter->trace;
4364 unsigned long entries;
4365 unsigned long total;
4366 const char *name = type->name;
4367
4368 get_total_entries(buf, &total, &entries);
4369
4370 seq_printf(m, "# %s latency trace v1.1.5 on %s\n",
4371 name, UTS_RELEASE);
4372 seq_puts(m, "# -----------------------------------"
4373 "---------------------------------\n");
4374 seq_printf(m, "# latency: %lu us, #%lu/%lu, CPU#%d |"
4375 " (M:%s VP:%d, KP:%d, SP:%d HP:%d",
4376 nsecs_to_usecs(data->saved_latency),
4377 entries,
4378 total,
4379 buf->cpu,
4380 preempt_model_none() ? "server" :
4381 preempt_model_voluntary() ? "desktop" :
4382 preempt_model_full() ? "preempt" :
4383 preempt_model_rt() ? "preempt_rt" :
4384 "unknown",
4385 /* These are reserved for later use */
4386 0, 0, 0, 0);
4387#ifdef CONFIG_SMP
4388 seq_printf(m, " #P:%d)\n", num_online_cpus());
4389#else
4390 seq_puts(m, ")\n");
4391#endif
4392 seq_puts(m, "# -----------------\n");
4393 seq_printf(m, "# | task: %.16s-%d "
4394 "(uid:%d nice:%ld policy:%ld rt_prio:%ld)\n",
4395 data->comm, data->pid,
4396 from_kuid_munged(seq_user_ns(m), data->uid), data->nice,
4397 data->policy, data->rt_priority);
4398 seq_puts(m, "# -----------------\n");
4399
4400 if (data->critical_start) {
4401 seq_puts(m, "# => started at: ");
4402 seq_print_ip_sym(&iter->seq, data->critical_start, sym_flags);
4403 trace_print_seq(m, &iter->seq);
4404 seq_puts(m, "\n# => ended at: ");
4405 seq_print_ip_sym(&iter->seq, data->critical_end, sym_flags);
4406 trace_print_seq(m, &iter->seq);
4407 seq_puts(m, "\n#\n");
4408 }
4409
4410 seq_puts(m, "#\n");
4411}
4412
4413static void test_cpu_buff_start(struct trace_iterator *iter)
4414{
4415 struct trace_seq *s = &iter->seq;
4416 struct trace_array *tr = iter->tr;
4417
4418 if (!(tr->trace_flags & TRACE_ITER_ANNOTATE))
4419 return;
4420
4421 if (!(iter->iter_flags & TRACE_FILE_ANNOTATE))
4422 return;
4423
4424 if (cpumask_available(iter->started) &&
4425 cpumask_test_cpu(iter->cpu, iter->started))
4426 return;
4427
4428 if (per_cpu_ptr(iter->array_buffer->data, iter->cpu)->skipped_entries)
4429 return;
4430
4431 if (cpumask_available(iter->started))
4432 cpumask_set_cpu(iter->cpu, iter->started);
4433
4434 /* Don't print started cpu buffer for the first entry of the trace */
4435 if (iter->idx > 1)
4436 trace_seq_printf(s, "##### CPU %u buffer started ####\n",
4437 iter->cpu);
4438}
4439
4440static enum print_line_t print_trace_fmt(struct trace_iterator *iter)
4441{
4442 struct trace_array *tr = iter->tr;
4443 struct trace_seq *s = &iter->seq;
4444 unsigned long sym_flags = (tr->trace_flags & TRACE_ITER_SYM_MASK);
4445 struct trace_entry *entry;
4446 struct trace_event *event;
4447
4448 entry = iter->ent;
4449
4450 test_cpu_buff_start(iter);
4451
4452 event = ftrace_find_event(entry->type);
4453
4454 if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO) {
4455 if (iter->iter_flags & TRACE_FILE_LAT_FMT)
4456 trace_print_lat_context(iter);
4457 else
4458 trace_print_context(iter);
4459 }
4460
4461 if (trace_seq_has_overflowed(s))
4462 return TRACE_TYPE_PARTIAL_LINE;
4463
4464 if (event) {
4465 if (tr->trace_flags & TRACE_ITER_FIELDS)
4466 return print_event_fields(iter, event);
4467 return event->funcs->trace(iter, sym_flags, event);
4468 }
4469
4470 trace_seq_printf(s, "Unknown type %d\n", entry->type);
4471
4472 return trace_handle_return(s);
4473}
4474
4475static enum print_line_t print_raw_fmt(struct trace_iterator *iter)
4476{
4477 struct trace_array *tr = iter->tr;
4478 struct trace_seq *s = &iter->seq;
4479 struct trace_entry *entry;
4480 struct trace_event *event;
4481
4482 entry = iter->ent;
4483
4484 if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO)
4485 trace_seq_printf(s, "%d %d %llu ",
4486 entry->pid, iter->cpu, iter->ts);
4487
4488 if (trace_seq_has_overflowed(s))
4489 return TRACE_TYPE_PARTIAL_LINE;
4490
4491 event = ftrace_find_event(entry->type);
4492 if (event)
4493 return event->funcs->raw(iter, 0, event);
4494
4495 trace_seq_printf(s, "%d ?\n", entry->type);
4496
4497 return trace_handle_return(s);
4498}
4499
4500static enum print_line_t print_hex_fmt(struct trace_iterator *iter)
4501{
4502 struct trace_array *tr = iter->tr;
4503 struct trace_seq *s = &iter->seq;
4504 unsigned char newline = '\n';
4505 struct trace_entry *entry;
4506 struct trace_event *event;
4507
4508 entry = iter->ent;
4509
4510 if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO) {
4511 SEQ_PUT_HEX_FIELD(s, entry->pid);
4512 SEQ_PUT_HEX_FIELD(s, iter->cpu);
4513 SEQ_PUT_HEX_FIELD(s, iter->ts);
4514 if (trace_seq_has_overflowed(s))
4515 return TRACE_TYPE_PARTIAL_LINE;
4516 }
4517
4518 event = ftrace_find_event(entry->type);
4519 if (event) {
4520 enum print_line_t ret = event->funcs->hex(iter, 0, event);
4521 if (ret != TRACE_TYPE_HANDLED)
4522 return ret;
4523 }
4524
4525 SEQ_PUT_FIELD(s, newline);
4526
4527 return trace_handle_return(s);
4528}
4529
4530static enum print_line_t print_bin_fmt(struct trace_iterator *iter)
4531{
4532 struct trace_array *tr = iter->tr;
4533 struct trace_seq *s = &iter->seq;
4534 struct trace_entry *entry;
4535 struct trace_event *event;
4536
4537 entry = iter->ent;
4538
4539 if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO) {
4540 SEQ_PUT_FIELD(s, entry->pid);
4541 SEQ_PUT_FIELD(s, iter->cpu);
4542 SEQ_PUT_FIELD(s, iter->ts);
4543 if (trace_seq_has_overflowed(s))
4544 return TRACE_TYPE_PARTIAL_LINE;
4545 }
4546
4547 event = ftrace_find_event(entry->type);
4548 return event ? event->funcs->binary(iter, 0, event) :
4549 TRACE_TYPE_HANDLED;
4550}
4551
4552int trace_empty(struct trace_iterator *iter)
4553{
4554 struct ring_buffer_iter *buf_iter;
4555 int cpu;
4556
4557 /* If we are looking at one CPU buffer, only check that one */
4558 if (iter->cpu_file != RING_BUFFER_ALL_CPUS) {
4559 cpu = iter->cpu_file;
4560 buf_iter = trace_buffer_iter(iter, cpu);
4561 if (buf_iter) {
4562 if (!ring_buffer_iter_empty(buf_iter))
4563 return 0;
4564 } else {
4565 if (!ring_buffer_empty_cpu(iter->array_buffer->buffer, cpu))
4566 return 0;
4567 }
4568 return 1;
4569 }
4570
4571 for_each_tracing_cpu(cpu) {
4572 buf_iter = trace_buffer_iter(iter, cpu);
4573 if (buf_iter) {
4574 if (!ring_buffer_iter_empty(buf_iter))
4575 return 0;
4576 } else {
4577 if (!ring_buffer_empty_cpu(iter->array_buffer->buffer, cpu))
4578 return 0;
4579 }
4580 }
4581
4582 return 1;
4583}
4584
4585/* Called with trace_event_read_lock() held. */
4586enum print_line_t print_trace_line(struct trace_iterator *iter)
4587{
4588 struct trace_array *tr = iter->tr;
4589 unsigned long trace_flags = tr->trace_flags;
4590 enum print_line_t ret;
4591
4592 if (iter->lost_events) {
4593 if (iter->lost_events == (unsigned long)-1)
4594 trace_seq_printf(&iter->seq, "CPU:%d [LOST EVENTS]\n",
4595 iter->cpu);
4596 else
4597 trace_seq_printf(&iter->seq, "CPU:%d [LOST %lu EVENTS]\n",
4598 iter->cpu, iter->lost_events);
4599 if (trace_seq_has_overflowed(&iter->seq))
4600 return TRACE_TYPE_PARTIAL_LINE;
4601 }
4602
4603 if (iter->trace && iter->trace->print_line) {
4604 ret = iter->trace->print_line(iter);
4605 if (ret != TRACE_TYPE_UNHANDLED)
4606 return ret;
4607 }
4608
4609 if (iter->ent->type == TRACE_BPUTS &&
4610 trace_flags & TRACE_ITER_PRINTK &&
4611 trace_flags & TRACE_ITER_PRINTK_MSGONLY)
4612 return trace_print_bputs_msg_only(iter);
4613
4614 if (iter->ent->type == TRACE_BPRINT &&
4615 trace_flags & TRACE_ITER_PRINTK &&
4616 trace_flags & TRACE_ITER_PRINTK_MSGONLY)
4617 return trace_print_bprintk_msg_only(iter);
4618
4619 if (iter->ent->type == TRACE_PRINT &&
4620 trace_flags & TRACE_ITER_PRINTK &&
4621 trace_flags & TRACE_ITER_PRINTK_MSGONLY)
4622 return trace_print_printk_msg_only(iter);
4623
4624 if (trace_flags & TRACE_ITER_BIN)
4625 return print_bin_fmt(iter);
4626
4627 if (trace_flags & TRACE_ITER_HEX)
4628 return print_hex_fmt(iter);
4629
4630 if (trace_flags & TRACE_ITER_RAW)
4631 return print_raw_fmt(iter);
4632
4633 return print_trace_fmt(iter);
4634}
4635
4636void trace_latency_header(struct seq_file *m)
4637{
4638 struct trace_iterator *iter = m->private;
4639 struct trace_array *tr = iter->tr;
4640
4641 /* print nothing if the buffers are empty */
4642 if (trace_empty(iter))
4643 return;
4644
4645 if (iter->iter_flags & TRACE_FILE_LAT_FMT)
4646 print_trace_header(m, iter);
4647
4648 if (!(tr->trace_flags & TRACE_ITER_VERBOSE))
4649 print_lat_help_header(m);
4650}
4651
4652void trace_default_header(struct seq_file *m)
4653{
4654 struct trace_iterator *iter = m->private;
4655 struct trace_array *tr = iter->tr;
4656 unsigned long trace_flags = tr->trace_flags;
4657
4658 if (!(trace_flags & TRACE_ITER_CONTEXT_INFO))
4659 return;
4660
4661 if (iter->iter_flags & TRACE_FILE_LAT_FMT) {
4662 /* print nothing if the buffers are empty */
4663 if (trace_empty(iter))
4664 return;
4665 print_trace_header(m, iter);
4666 if (!(trace_flags & TRACE_ITER_VERBOSE))
4667 print_lat_help_header(m);
4668 } else {
4669 if (!(trace_flags & TRACE_ITER_VERBOSE)) {
4670 if (trace_flags & TRACE_ITER_IRQ_INFO)
4671 print_func_help_header_irq(iter->array_buffer,
4672 m, trace_flags);
4673 else
4674 print_func_help_header(iter->array_buffer, m,
4675 trace_flags);
4676 }
4677 }
4678}
4679
4680static void test_ftrace_alive(struct seq_file *m)
4681{
4682 if (!ftrace_is_dead())
4683 return;
4684 seq_puts(m, "# WARNING: FUNCTION TRACING IS CORRUPTED\n"
4685 "# MAY BE MISSING FUNCTION EVENTS\n");
4686}
4687
4688#ifdef CONFIG_TRACER_MAX_TRACE
4689static void show_snapshot_main_help(struct seq_file *m)
4690{
4691 seq_puts(m, "# echo 0 > snapshot : Clears and frees snapshot buffer\n"
4692 "# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.\n"
4693 "# Takes a snapshot of the main buffer.\n"
4694 "# echo 2 > snapshot : Clears snapshot buffer (but does not allocate or free)\n"
4695 "# (Doesn't have to be '2' works with any number that\n"
4696 "# is not a '0' or '1')\n");
4697}
4698
4699static void show_snapshot_percpu_help(struct seq_file *m)
4700{
4701 seq_puts(m, "# echo 0 > snapshot : Invalid for per_cpu snapshot file.\n");
4702#ifdef CONFIG_RING_BUFFER_ALLOW_SWAP
4703 seq_puts(m, "# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.\n"
4704 "# Takes a snapshot of the main buffer for this cpu.\n");
4705#else
4706 seq_puts(m, "# echo 1 > snapshot : Not supported with this kernel.\n"
4707 "# Must use main snapshot file to allocate.\n");
4708#endif
4709 seq_puts(m, "# echo 2 > snapshot : Clears this cpu's snapshot buffer (but does not allocate)\n"
4710 "# (Doesn't have to be '2' works with any number that\n"
4711 "# is not a '0' or '1')\n");
4712}
4713
4714static void print_snapshot_help(struct seq_file *m, struct trace_iterator *iter)
4715{
4716 if (iter->tr->allocated_snapshot)
4717 seq_puts(m, "#\n# * Snapshot is allocated *\n#\n");
4718 else
4719 seq_puts(m, "#\n# * Snapshot is freed *\n#\n");
4720
4721 seq_puts(m, "# Snapshot commands:\n");
4722 if (iter->cpu_file == RING_BUFFER_ALL_CPUS)
4723 show_snapshot_main_help(m);
4724 else
4725 show_snapshot_percpu_help(m);
4726}
4727#else
4728/* Should never be called */
4729static inline void print_snapshot_help(struct seq_file *m, struct trace_iterator *iter) { }
4730#endif
4731
4732static int s_show(struct seq_file *m, void *v)
4733{
4734 struct trace_iterator *iter = v;
4735 int ret;
4736
4737 if (iter->ent == NULL) {
4738 if (iter->tr) {
4739 seq_printf(m, "# tracer: %s\n", iter->trace->name);
4740 seq_puts(m, "#\n");
4741 test_ftrace_alive(m);
4742 }
4743 if (iter->snapshot && trace_empty(iter))
4744 print_snapshot_help(m, iter);
4745 else if (iter->trace && iter->trace->print_header)
4746 iter->trace->print_header(m);
4747 else
4748 trace_default_header(m);
4749
4750 } else if (iter->leftover) {
4751 /*
4752 * If we filled the seq_file buffer earlier, we
4753 * want to just show it now.
4754 */
4755 ret = trace_print_seq(m, &iter->seq);
4756
4757 /* ret should this time be zero, but you never know */
4758 iter->leftover = ret;
4759
4760 } else {
4761 ret = print_trace_line(iter);
4762 if (ret == TRACE_TYPE_PARTIAL_LINE) {
4763 iter->seq.full = 0;
4764 trace_seq_puts(&iter->seq, "[LINE TOO BIG]\n");
4765 }
4766 ret = trace_print_seq(m, &iter->seq);
4767 /*
4768 * If we overflow the seq_file buffer, then it will
4769 * ask us for this data again at start up.
4770 * Use that instead.
4771 * ret is 0 if seq_file write succeeded.
4772 * -1 otherwise.
4773 */
4774 iter->leftover = ret;
4775 }
4776
4777 return 0;
4778}
4779
4780/*
4781 * Should be used after trace_array_get(), trace_types_lock
4782 * ensures that i_cdev was already initialized.
4783 */
4784static inline int tracing_get_cpu(struct inode *inode)
4785{
4786 if (inode->i_cdev) /* See trace_create_cpu_file() */
4787 return (long)inode->i_cdev - 1;
4788 return RING_BUFFER_ALL_CPUS;
4789}
4790
4791static const struct seq_operations tracer_seq_ops = {
4792 .start = s_start,
4793 .next = s_next,
4794 .stop = s_stop,
4795 .show = s_show,
4796};
4797
4798/*
4799 * Note, as iter itself can be allocated and freed in different
4800 * ways, this function is only used to free its content, and not
4801 * the iterator itself. The only requirement to all the allocations
4802 * is that it must zero all fields (kzalloc), as freeing works with
4803 * ethier allocated content or NULL.
4804 */
4805static void free_trace_iter_content(struct trace_iterator *iter)
4806{
4807 /* The fmt is either NULL, allocated or points to static_fmt_buf */
4808 if (iter->fmt != static_fmt_buf)
4809 kfree(iter->fmt);
4810
4811 kfree(iter->temp);
4812 kfree(iter->buffer_iter);
4813 mutex_destroy(&iter->mutex);
4814 free_cpumask_var(iter->started);
4815}
4816
4817static struct trace_iterator *
4818__tracing_open(struct inode *inode, struct file *file, bool snapshot)
4819{
4820 struct trace_array *tr = inode->i_private;
4821 struct trace_iterator *iter;
4822 int cpu;
4823
4824 if (tracing_disabled)
4825 return ERR_PTR(-ENODEV);
4826
4827 iter = __seq_open_private(file, &tracer_seq_ops, sizeof(*iter));
4828 if (!iter)
4829 return ERR_PTR(-ENOMEM);
4830
4831 iter->buffer_iter = kcalloc(nr_cpu_ids, sizeof(*iter->buffer_iter),
4832 GFP_KERNEL);
4833 if (!iter->buffer_iter)
4834 goto release;
4835
4836 /*
4837 * trace_find_next_entry() may need to save off iter->ent.
4838 * It will place it into the iter->temp buffer. As most
4839 * events are less than 128, allocate a buffer of that size.
4840 * If one is greater, then trace_find_next_entry() will
4841 * allocate a new buffer to adjust for the bigger iter->ent.
4842 * It's not critical if it fails to get allocated here.
4843 */
4844 iter->temp = kmalloc(128, GFP_KERNEL);
4845 if (iter->temp)
4846 iter->temp_size = 128;
4847
4848 /*
4849 * trace_event_printf() may need to modify given format
4850 * string to replace %p with %px so that it shows real address
4851 * instead of hash value. However, that is only for the event
4852 * tracing, other tracer may not need. Defer the allocation
4853 * until it is needed.
4854 */
4855 iter->fmt = NULL;
4856 iter->fmt_size = 0;
4857
4858 mutex_lock(&trace_types_lock);
4859 iter->trace = tr->current_trace;
4860
4861 if (!zalloc_cpumask_var(&iter->started, GFP_KERNEL))
4862 goto fail;
4863
4864 iter->tr = tr;
4865
4866#ifdef CONFIG_TRACER_MAX_TRACE
4867 /* Currently only the top directory has a snapshot */
4868 if (tr->current_trace->print_max || snapshot)
4869 iter->array_buffer = &tr->max_buffer;
4870 else
4871#endif
4872 iter->array_buffer = &tr->array_buffer;
4873 iter->snapshot = snapshot;
4874 iter->pos = -1;
4875 iter->cpu_file = tracing_get_cpu(inode);
4876 mutex_init(&iter->mutex);
4877
4878 /* Notify the tracer early; before we stop tracing. */
4879 if (iter->trace->open)
4880 iter->trace->open(iter);
4881
4882 /* Annotate start of buffers if we had overruns */
4883 if (ring_buffer_overruns(iter->array_buffer->buffer))
4884 iter->iter_flags |= TRACE_FILE_ANNOTATE;
4885
4886 /* Output in nanoseconds only if we are using a clock in nanoseconds. */
4887 if (trace_clocks[tr->clock_id].in_ns)
4888 iter->iter_flags |= TRACE_FILE_TIME_IN_NS;
4889
4890 /*
4891 * If pause-on-trace is enabled, then stop the trace while
4892 * dumping, unless this is the "snapshot" file
4893 */
4894 if (!iter->snapshot && (tr->trace_flags & TRACE_ITER_PAUSE_ON_TRACE))
4895 tracing_stop_tr(tr);
4896
4897 if (iter->cpu_file == RING_BUFFER_ALL_CPUS) {
4898 for_each_tracing_cpu(cpu) {
4899 iter->buffer_iter[cpu] =
4900 ring_buffer_read_prepare(iter->array_buffer->buffer,
4901 cpu, GFP_KERNEL);
4902 }
4903 ring_buffer_read_prepare_sync();
4904 for_each_tracing_cpu(cpu) {
4905 ring_buffer_read_start(iter->buffer_iter[cpu]);
4906 tracing_iter_reset(iter, cpu);
4907 }
4908 } else {
4909 cpu = iter->cpu_file;
4910 iter->buffer_iter[cpu] =
4911 ring_buffer_read_prepare(iter->array_buffer->buffer,
4912 cpu, GFP_KERNEL);
4913 ring_buffer_read_prepare_sync();
4914 ring_buffer_read_start(iter->buffer_iter[cpu]);
4915 tracing_iter_reset(iter, cpu);
4916 }
4917
4918 mutex_unlock(&trace_types_lock);
4919
4920 return iter;
4921
4922 fail:
4923 mutex_unlock(&trace_types_lock);
4924 free_trace_iter_content(iter);
4925release:
4926 seq_release_private(inode, file);
4927 return ERR_PTR(-ENOMEM);
4928}
4929
4930int tracing_open_generic(struct inode *inode, struct file *filp)
4931{
4932 int ret;
4933
4934 ret = tracing_check_open_get_tr(NULL);
4935 if (ret)
4936 return ret;
4937
4938 filp->private_data = inode->i_private;
4939 return 0;
4940}
4941
4942bool tracing_is_disabled(void)
4943{
4944 return (tracing_disabled) ? true: false;
4945}
4946
4947/*
4948 * Open and update trace_array ref count.
4949 * Must have the current trace_array passed to it.
4950 */
4951int tracing_open_generic_tr(struct inode *inode, struct file *filp)
4952{
4953 struct trace_array *tr = inode->i_private;
4954 int ret;
4955
4956 ret = tracing_check_open_get_tr(tr);
4957 if (ret)
4958 return ret;
4959
4960 filp->private_data = inode->i_private;
4961
4962 return 0;
4963}
4964
4965/*
4966 * The private pointer of the inode is the trace_event_file.
4967 * Update the tr ref count associated to it.
4968 */
4969int tracing_open_file_tr(struct inode *inode, struct file *filp)
4970{
4971 struct trace_event_file *file = inode->i_private;
4972 int ret;
4973
4974 ret = tracing_check_open_get_tr(file->tr);
4975 if (ret)
4976 return ret;
4977
4978 mutex_lock(&event_mutex);
4979
4980 /* Fail if the file is marked for removal */
4981 if (file->flags & EVENT_FILE_FL_FREED) {
4982 trace_array_put(file->tr);
4983 ret = -ENODEV;
4984 } else {
4985 event_file_get(file);
4986 }
4987
4988 mutex_unlock(&event_mutex);
4989 if (ret)
4990 return ret;
4991
4992 filp->private_data = inode->i_private;
4993
4994 return 0;
4995}
4996
4997int tracing_release_file_tr(struct inode *inode, struct file *filp)
4998{
4999 struct trace_event_file *file = inode->i_private;
5000
5001 trace_array_put(file->tr);
5002 event_file_put(file);
5003
5004 return 0;
5005}
5006
5007int tracing_single_release_file_tr(struct inode *inode, struct file *filp)
5008{
5009 tracing_release_file_tr(inode, filp);
5010 return single_release(inode, filp);
5011}
5012
5013static int tracing_mark_open(struct inode *inode, struct file *filp)
5014{
5015 stream_open(inode, filp);
5016 return tracing_open_generic_tr(inode, filp);
5017}
5018
5019static int tracing_release(struct inode *inode, struct file *file)
5020{
5021 struct trace_array *tr = inode->i_private;
5022 struct seq_file *m = file->private_data;
5023 struct trace_iterator *iter;
5024 int cpu;
5025
5026 if (!(file->f_mode & FMODE_READ)) {
5027 trace_array_put(tr);
5028 return 0;
5029 }
5030
5031 /* Writes do not use seq_file */
5032 iter = m->private;
5033 mutex_lock(&trace_types_lock);
5034
5035 for_each_tracing_cpu(cpu) {
5036 if (iter->buffer_iter[cpu])
5037 ring_buffer_read_finish(iter->buffer_iter[cpu]);
5038 }
5039
5040 if (iter->trace && iter->trace->close)
5041 iter->trace->close(iter);
5042
5043 if (!iter->snapshot && tr->stop_count)
5044 /* reenable tracing if it was previously enabled */
5045 tracing_start_tr(tr);
5046
5047 __trace_array_put(tr);
5048
5049 mutex_unlock(&trace_types_lock);
5050
5051 free_trace_iter_content(iter);
5052 seq_release_private(inode, file);
5053
5054 return 0;
5055}
5056
5057int tracing_release_generic_tr(struct inode *inode, struct file *file)
5058{
5059 struct trace_array *tr = inode->i_private;
5060
5061 trace_array_put(tr);
5062 return 0;
5063}
5064
5065static int tracing_single_release_tr(struct inode *inode, struct file *file)
5066{
5067 struct trace_array *tr = inode->i_private;
5068
5069 trace_array_put(tr);
5070
5071 return single_release(inode, file);
5072}
5073
5074static int tracing_open(struct inode *inode, struct file *file)
5075{
5076 struct trace_array *tr = inode->i_private;
5077 struct trace_iterator *iter;
5078 int ret;
5079
5080 ret = tracing_check_open_get_tr(tr);
5081 if (ret)
5082 return ret;
5083
5084 /* If this file was open for write, then erase contents */
5085 if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
5086 int cpu = tracing_get_cpu(inode);
5087 struct array_buffer *trace_buf = &tr->array_buffer;
5088
5089#ifdef CONFIG_TRACER_MAX_TRACE
5090 if (tr->current_trace->print_max)
5091 trace_buf = &tr->max_buffer;
5092#endif
5093
5094 if (cpu == RING_BUFFER_ALL_CPUS)
5095 tracing_reset_online_cpus(trace_buf);
5096 else
5097 tracing_reset_cpu(trace_buf, cpu);
5098 }
5099
5100 if (file->f_mode & FMODE_READ) {
5101 iter = __tracing_open(inode, file, false);
5102 if (IS_ERR(iter))
5103 ret = PTR_ERR(iter);
5104 else if (tr->trace_flags & TRACE_ITER_LATENCY_FMT)
5105 iter->iter_flags |= TRACE_FILE_LAT_FMT;
5106 }
5107
5108 if (ret < 0)
5109 trace_array_put(tr);
5110
5111 return ret;
5112}
5113
5114/*
5115 * Some tracers are not suitable for instance buffers.
5116 * A tracer is always available for the global array (toplevel)
5117 * or if it explicitly states that it is.
5118 */
5119static bool
5120trace_ok_for_array(struct tracer *t, struct trace_array *tr)
5121{
5122 return (tr->flags & TRACE_ARRAY_FL_GLOBAL) || t->allow_instances;
5123}
5124
5125/* Find the next tracer that this trace array may use */
5126static struct tracer *
5127get_tracer_for_array(struct trace_array *tr, struct tracer *t)
5128{
5129 while (t && !trace_ok_for_array(t, tr))
5130 t = t->next;
5131
5132 return t;
5133}
5134
5135static void *
5136t_next(struct seq_file *m, void *v, loff_t *pos)
5137{
5138 struct trace_array *tr = m->private;
5139 struct tracer *t = v;
5140
5141 (*pos)++;
5142
5143 if (t)
5144 t = get_tracer_for_array(tr, t->next);
5145
5146 return t;
5147}
5148
5149static void *t_start(struct seq_file *m, loff_t *pos)
5150{
5151 struct trace_array *tr = m->private;
5152 struct tracer *t;
5153 loff_t l = 0;
5154
5155 mutex_lock(&trace_types_lock);
5156
5157 t = get_tracer_for_array(tr, trace_types);
5158 for (; t && l < *pos; t = t_next(m, t, &l))
5159 ;
5160
5161 return t;
5162}
5163
5164static void t_stop(struct seq_file *m, void *p)
5165{
5166 mutex_unlock(&trace_types_lock);
5167}
5168
5169static int t_show(struct seq_file *m, void *v)
5170{
5171 struct tracer *t = v;
5172
5173 if (!t)
5174 return 0;
5175
5176 seq_puts(m, t->name);
5177 if (t->next)
5178 seq_putc(m, ' ');
5179 else
5180 seq_putc(m, '\n');
5181
5182 return 0;
5183}
5184
5185static const struct seq_operations show_traces_seq_ops = {
5186 .start = t_start,
5187 .next = t_next,
5188 .stop = t_stop,
5189 .show = t_show,
5190};
5191
5192static int show_traces_open(struct inode *inode, struct file *file)
5193{
5194 struct trace_array *tr = inode->i_private;
5195 struct seq_file *m;
5196 int ret;
5197
5198 ret = tracing_check_open_get_tr(tr);
5199 if (ret)
5200 return ret;
5201
5202 ret = seq_open(file, &show_traces_seq_ops);
5203 if (ret) {
5204 trace_array_put(tr);
5205 return ret;
5206 }
5207
5208 m = file->private_data;
5209 m->private = tr;
5210
5211 return 0;
5212}
5213
5214static int show_traces_release(struct inode *inode, struct file *file)
5215{
5216 struct trace_array *tr = inode->i_private;
5217
5218 trace_array_put(tr);
5219 return seq_release(inode, file);
5220}
5221
5222static ssize_t
5223tracing_write_stub(struct file *filp, const char __user *ubuf,
5224 size_t count, loff_t *ppos)
5225{
5226 return count;
5227}
5228
5229loff_t tracing_lseek(struct file *file, loff_t offset, int whence)
5230{
5231 int ret;
5232
5233 if (file->f_mode & FMODE_READ)
5234 ret = seq_lseek(file, offset, whence);
5235 else
5236 file->f_pos = ret = 0;
5237
5238 return ret;
5239}
5240
5241static const struct file_operations tracing_fops = {
5242 .open = tracing_open,
5243 .read = seq_read,
5244 .read_iter = seq_read_iter,
5245 .splice_read = copy_splice_read,
5246 .write = tracing_write_stub,
5247 .llseek = tracing_lseek,
5248 .release = tracing_release,
5249};
5250
5251static const struct file_operations show_traces_fops = {
5252 .open = show_traces_open,
5253 .read = seq_read,
5254 .llseek = seq_lseek,
5255 .release = show_traces_release,
5256};
5257
5258static ssize_t
5259tracing_cpumask_read(struct file *filp, char __user *ubuf,
5260 size_t count, loff_t *ppos)
5261{
5262 struct trace_array *tr = file_inode(filp)->i_private;
5263 char *mask_str;
5264 int len;
5265
5266 len = snprintf(NULL, 0, "%*pb\n",
5267 cpumask_pr_args(tr->tracing_cpumask)) + 1;
5268 mask_str = kmalloc(len, GFP_KERNEL);
5269 if (!mask_str)
5270 return -ENOMEM;
5271
5272 len = snprintf(mask_str, len, "%*pb\n",
5273 cpumask_pr_args(tr->tracing_cpumask));
5274 if (len >= count) {
5275 count = -EINVAL;
5276 goto out_err;
5277 }
5278 count = simple_read_from_buffer(ubuf, count, ppos, mask_str, len);
5279
5280out_err:
5281 kfree(mask_str);
5282
5283 return count;
5284}
5285
5286int tracing_set_cpumask(struct trace_array *tr,
5287 cpumask_var_t tracing_cpumask_new)
5288{
5289 int cpu;
5290
5291 if (!tr)
5292 return -EINVAL;
5293
5294 local_irq_disable();
5295 arch_spin_lock(&tr->max_lock);
5296 for_each_tracing_cpu(cpu) {
5297 /*
5298 * Increase/decrease the disabled counter if we are
5299 * about to flip a bit in the cpumask:
5300 */
5301 if (cpumask_test_cpu(cpu, tr->tracing_cpumask) &&
5302 !cpumask_test_cpu(cpu, tracing_cpumask_new)) {
5303 atomic_inc(&per_cpu_ptr(tr->array_buffer.data, cpu)->disabled);
5304 ring_buffer_record_disable_cpu(tr->array_buffer.buffer, cpu);
5305#ifdef CONFIG_TRACER_MAX_TRACE
5306 ring_buffer_record_disable_cpu(tr->max_buffer.buffer, cpu);
5307#endif
5308 }
5309 if (!cpumask_test_cpu(cpu, tr->tracing_cpumask) &&
5310 cpumask_test_cpu(cpu, tracing_cpumask_new)) {
5311 atomic_dec(&per_cpu_ptr(tr->array_buffer.data, cpu)->disabled);
5312 ring_buffer_record_enable_cpu(tr->array_buffer.buffer, cpu);
5313#ifdef CONFIG_TRACER_MAX_TRACE
5314 ring_buffer_record_enable_cpu(tr->max_buffer.buffer, cpu);
5315#endif
5316 }
5317 }
5318 arch_spin_unlock(&tr->max_lock);
5319 local_irq_enable();
5320
5321 cpumask_copy(tr->tracing_cpumask, tracing_cpumask_new);
5322
5323 return 0;
5324}
5325
5326static ssize_t
5327tracing_cpumask_write(struct file *filp, const char __user *ubuf,
5328 size_t count, loff_t *ppos)
5329{
5330 struct trace_array *tr = file_inode(filp)->i_private;
5331 cpumask_var_t tracing_cpumask_new;
5332 int err;
5333
5334 if (!zalloc_cpumask_var(&tracing_cpumask_new, GFP_KERNEL))
5335 return -ENOMEM;
5336
5337 err = cpumask_parse_user(ubuf, count, tracing_cpumask_new);
5338 if (err)
5339 goto err_free;
5340
5341 err = tracing_set_cpumask(tr, tracing_cpumask_new);
5342 if (err)
5343 goto err_free;
5344
5345 free_cpumask_var(tracing_cpumask_new);
5346
5347 return count;
5348
5349err_free:
5350 free_cpumask_var(tracing_cpumask_new);
5351
5352 return err;
5353}
5354
5355static const struct file_operations tracing_cpumask_fops = {
5356 .open = tracing_open_generic_tr,
5357 .read = tracing_cpumask_read,
5358 .write = tracing_cpumask_write,
5359 .release = tracing_release_generic_tr,
5360 .llseek = generic_file_llseek,
5361};
5362
5363static int tracing_trace_options_show(struct seq_file *m, void *v)
5364{
5365 struct tracer_opt *trace_opts;
5366 struct trace_array *tr = m->private;
5367 u32 tracer_flags;
5368 int i;
5369
5370 mutex_lock(&trace_types_lock);
5371 tracer_flags = tr->current_trace->flags->val;
5372 trace_opts = tr->current_trace->flags->opts;
5373
5374 for (i = 0; trace_options[i]; i++) {
5375 if (tr->trace_flags & (1 << i))
5376 seq_printf(m, "%s\n", trace_options[i]);
5377 else
5378 seq_printf(m, "no%s\n", trace_options[i]);
5379 }
5380
5381 for (i = 0; trace_opts[i].name; i++) {
5382 if (tracer_flags & trace_opts[i].bit)
5383 seq_printf(m, "%s\n", trace_opts[i].name);
5384 else
5385 seq_printf(m, "no%s\n", trace_opts[i].name);
5386 }
5387 mutex_unlock(&trace_types_lock);
5388
5389 return 0;
5390}
5391
5392static int __set_tracer_option(struct trace_array *tr,
5393 struct tracer_flags *tracer_flags,
5394 struct tracer_opt *opts, int neg)
5395{
5396 struct tracer *trace = tracer_flags->trace;
5397 int ret;
5398
5399 ret = trace->set_flag(tr, tracer_flags->val, opts->bit, !neg);
5400 if (ret)
5401 return ret;
5402
5403 if (neg)
5404 tracer_flags->val &= ~opts->bit;
5405 else
5406 tracer_flags->val |= opts->bit;
5407 return 0;
5408}
5409
5410/* Try to assign a tracer specific option */
5411static int set_tracer_option(struct trace_array *tr, char *cmp, int neg)
5412{
5413 struct tracer *trace = tr->current_trace;
5414 struct tracer_flags *tracer_flags = trace->flags;
5415 struct tracer_opt *opts = NULL;
5416 int i;
5417
5418 for (i = 0; tracer_flags->opts[i].name; i++) {
5419 opts = &tracer_flags->opts[i];
5420
5421 if (strcmp(cmp, opts->name) == 0)
5422 return __set_tracer_option(tr, trace->flags, opts, neg);
5423 }
5424
5425 return -EINVAL;
5426}
5427
5428/* Some tracers require overwrite to stay enabled */
5429int trace_keep_overwrite(struct tracer *tracer, u32 mask, int set)
5430{
5431 if (tracer->enabled && (mask & TRACE_ITER_OVERWRITE) && !set)
5432 return -1;
5433
5434 return 0;
5435}
5436
5437int set_tracer_flag(struct trace_array *tr, unsigned int mask, int enabled)
5438{
5439 int *map;
5440
5441 if ((mask == TRACE_ITER_RECORD_TGID) ||
5442 (mask == TRACE_ITER_RECORD_CMD))
5443 lockdep_assert_held(&event_mutex);
5444
5445 /* do nothing if flag is already set */
5446 if (!!(tr->trace_flags & mask) == !!enabled)
5447 return 0;
5448
5449 /* Give the tracer a chance to approve the change */
5450 if (tr->current_trace->flag_changed)
5451 if (tr->current_trace->flag_changed(tr, mask, !!enabled))
5452 return -EINVAL;
5453
5454 if (enabled)
5455 tr->trace_flags |= mask;
5456 else
5457 tr->trace_flags &= ~mask;
5458
5459 if (mask == TRACE_ITER_RECORD_CMD)
5460 trace_event_enable_cmd_record(enabled);
5461
5462 if (mask == TRACE_ITER_RECORD_TGID) {
5463 if (!tgid_map) {
5464 tgid_map_max = pid_max;
5465 map = kvcalloc(tgid_map_max + 1, sizeof(*tgid_map),
5466 GFP_KERNEL);
5467
5468 /*
5469 * Pairs with smp_load_acquire() in
5470 * trace_find_tgid_ptr() to ensure that if it observes
5471 * the tgid_map we just allocated then it also observes
5472 * the corresponding tgid_map_max value.
5473 */
5474 smp_store_release(&tgid_map, map);
5475 }
5476 if (!tgid_map) {
5477 tr->trace_flags &= ~TRACE_ITER_RECORD_TGID;
5478 return -ENOMEM;
5479 }
5480
5481 trace_event_enable_tgid_record(enabled);
5482 }
5483
5484 if (mask == TRACE_ITER_EVENT_FORK)
5485 trace_event_follow_fork(tr, enabled);
5486
5487 if (mask == TRACE_ITER_FUNC_FORK)
5488 ftrace_pid_follow_fork(tr, enabled);
5489
5490 if (mask == TRACE_ITER_OVERWRITE) {
5491 ring_buffer_change_overwrite(tr->array_buffer.buffer, enabled);
5492#ifdef CONFIG_TRACER_MAX_TRACE
5493 ring_buffer_change_overwrite(tr->max_buffer.buffer, enabled);
5494#endif
5495 }
5496
5497 if (mask == TRACE_ITER_PRINTK) {
5498 trace_printk_start_stop_comm(enabled);
5499 trace_printk_control(enabled);
5500 }
5501
5502 return 0;
5503}
5504
5505int trace_set_options(struct trace_array *tr, char *option)
5506{
5507 char *cmp;
5508 int neg = 0;
5509 int ret;
5510 size_t orig_len = strlen(option);
5511 int len;
5512
5513 cmp = strstrip(option);
5514
5515 len = str_has_prefix(cmp, "no");
5516 if (len)
5517 neg = 1;
5518
5519 cmp += len;
5520
5521 mutex_lock(&event_mutex);
5522 mutex_lock(&trace_types_lock);
5523
5524 ret = match_string(trace_options, -1, cmp);
5525 /* If no option could be set, test the specific tracer options */
5526 if (ret < 0)
5527 ret = set_tracer_option(tr, cmp, neg);
5528 else
5529 ret = set_tracer_flag(tr, 1 << ret, !neg);
5530
5531 mutex_unlock(&trace_types_lock);
5532 mutex_unlock(&event_mutex);
5533
5534 /*
5535 * If the first trailing whitespace is replaced with '\0' by strstrip,
5536 * turn it back into a space.
5537 */
5538 if (orig_len > strlen(option))
5539 option[strlen(option)] = ' ';
5540
5541 return ret;
5542}
5543
5544static void __init apply_trace_boot_options(void)
5545{
5546 char *buf = trace_boot_options_buf;
5547 char *option;
5548
5549 while (true) {
5550 option = strsep(&buf, ",");
5551
5552 if (!option)
5553 break;
5554
5555 if (*option)
5556 trace_set_options(&global_trace, option);
5557
5558 /* Put back the comma to allow this to be called again */
5559 if (buf)
5560 *(buf - 1) = ',';
5561 }
5562}
5563
5564static ssize_t
5565tracing_trace_options_write(struct file *filp, const char __user *ubuf,
5566 size_t cnt, loff_t *ppos)
5567{
5568 struct seq_file *m = filp->private_data;
5569 struct trace_array *tr = m->private;
5570 char buf[64];
5571 int ret;
5572
5573 if (cnt >= sizeof(buf))
5574 return -EINVAL;
5575
5576 if (copy_from_user(buf, ubuf, cnt))
5577 return -EFAULT;
5578
5579 buf[cnt] = 0;
5580
5581 ret = trace_set_options(tr, buf);
5582 if (ret < 0)
5583 return ret;
5584
5585 *ppos += cnt;
5586
5587 return cnt;
5588}
5589
5590static int tracing_trace_options_open(struct inode *inode, struct file *file)
5591{
5592 struct trace_array *tr = inode->i_private;
5593 int ret;
5594
5595 ret = tracing_check_open_get_tr(tr);
5596 if (ret)
5597 return ret;
5598
5599 ret = single_open(file, tracing_trace_options_show, inode->i_private);
5600 if (ret < 0)
5601 trace_array_put(tr);
5602
5603 return ret;
5604}
5605
5606static const struct file_operations tracing_iter_fops = {
5607 .open = tracing_trace_options_open,
5608 .read = seq_read,
5609 .llseek = seq_lseek,
5610 .release = tracing_single_release_tr,
5611 .write = tracing_trace_options_write,
5612};
5613
5614static const char readme_msg[] =
5615 "tracing mini-HOWTO:\n\n"
5616 "# echo 0 > tracing_on : quick way to disable tracing\n"
5617 "# echo 1 > tracing_on : quick way to re-enable tracing\n\n"
5618 " Important files:\n"
5619 " trace\t\t\t- The static contents of the buffer\n"
5620 "\t\t\t To clear the buffer write into this file: echo > trace\n"
5621 " trace_pipe\t\t- A consuming read to see the contents of the buffer\n"
5622 " current_tracer\t- function and latency tracers\n"
5623 " available_tracers\t- list of configured tracers for current_tracer\n"
5624 " error_log\t- error log for failed commands (that support it)\n"
5625 " buffer_size_kb\t- view and modify size of per cpu buffer\n"
5626 " buffer_total_size_kb - view total size of all cpu buffers\n\n"
5627 " trace_clock\t\t- change the clock used to order events\n"
5628 " local: Per cpu clock but may not be synced across CPUs\n"
5629 " global: Synced across CPUs but slows tracing down.\n"
5630 " counter: Not a clock, but just an increment\n"
5631 " uptime: Jiffy counter from time of boot\n"
5632 " perf: Same clock that perf events use\n"
5633#ifdef CONFIG_X86_64
5634 " x86-tsc: TSC cycle counter\n"
5635#endif
5636 "\n timestamp_mode\t- view the mode used to timestamp events\n"
5637 " delta: Delta difference against a buffer-wide timestamp\n"
5638 " absolute: Absolute (standalone) timestamp\n"
5639 "\n trace_marker\t\t- Writes into this file writes into the kernel buffer\n"
5640 "\n trace_marker_raw\t\t- Writes into this file writes binary data into the kernel buffer\n"
5641 " tracing_cpumask\t- Limit which CPUs to trace\n"
5642 " instances\t\t- Make sub-buffers with: mkdir instances/foo\n"
5643 "\t\t\t Remove sub-buffer with rmdir\n"
5644 " trace_options\t\t- Set format or modify how tracing happens\n"
5645 "\t\t\t Disable an option by prefixing 'no' to the\n"
5646 "\t\t\t option name\n"
5647 " saved_cmdlines_size\t- echo command number in here to store comm-pid list\n"
5648#ifdef CONFIG_DYNAMIC_FTRACE
5649 "\n available_filter_functions - list of functions that can be filtered on\n"
5650 " set_ftrace_filter\t- echo function name in here to only trace these\n"
5651 "\t\t\t functions\n"
5652 "\t accepts: func_full_name or glob-matching-pattern\n"
5653 "\t modules: Can select a group via module\n"
5654 "\t Format: :mod:<module-name>\n"
5655 "\t example: echo :mod:ext3 > set_ftrace_filter\n"
5656 "\t triggers: a command to perform when function is hit\n"
5657 "\t Format: <function>:<trigger>[:count]\n"
5658 "\t trigger: traceon, traceoff\n"
5659 "\t\t enable_event:<system>:<event>\n"
5660 "\t\t disable_event:<system>:<event>\n"
5661#ifdef CONFIG_STACKTRACE
5662 "\t\t stacktrace\n"
5663#endif
5664#ifdef CONFIG_TRACER_SNAPSHOT
5665 "\t\t snapshot\n"
5666#endif
5667 "\t\t dump\n"
5668 "\t\t cpudump\n"
5669 "\t example: echo do_fault:traceoff > set_ftrace_filter\n"
5670 "\t echo do_trap:traceoff:3 > set_ftrace_filter\n"
5671 "\t The first one will disable tracing every time do_fault is hit\n"
5672 "\t The second will disable tracing at most 3 times when do_trap is hit\n"
5673 "\t The first time do trap is hit and it disables tracing, the\n"
5674 "\t counter will decrement to 2. If tracing is already disabled,\n"
5675 "\t the counter will not decrement. It only decrements when the\n"
5676 "\t trigger did work\n"
5677 "\t To remove trigger without count:\n"
5678 "\t echo '!<function>:<trigger> > set_ftrace_filter\n"
5679 "\t To remove trigger with a count:\n"
5680 "\t echo '!<function>:<trigger>:0 > set_ftrace_filter\n"
5681 " set_ftrace_notrace\t- echo function name in here to never trace.\n"
5682 "\t accepts: func_full_name, *func_end, func_begin*, *func_middle*\n"
5683 "\t modules: Can select a group via module command :mod:\n"
5684 "\t Does not accept triggers\n"
5685#endif /* CONFIG_DYNAMIC_FTRACE */
5686#ifdef CONFIG_FUNCTION_TRACER
5687 " set_ftrace_pid\t- Write pid(s) to only function trace those pids\n"
5688 "\t\t (function)\n"
5689 " set_ftrace_notrace_pid\t- Write pid(s) to not function trace those pids\n"
5690 "\t\t (function)\n"
5691#endif
5692#ifdef CONFIG_FUNCTION_GRAPH_TRACER
5693 " set_graph_function\t- Trace the nested calls of a function (function_graph)\n"
5694 " set_graph_notrace\t- Do not trace the nested calls of a function (function_graph)\n"
5695 " max_graph_depth\t- Trace a limited depth of nested calls (0 is unlimited)\n"
5696#endif
5697#ifdef CONFIG_TRACER_SNAPSHOT
5698 "\n snapshot\t\t- Like 'trace' but shows the content of the static\n"
5699 "\t\t\t snapshot buffer. Read the contents for more\n"
5700 "\t\t\t information\n"
5701#endif
5702#ifdef CONFIG_STACK_TRACER
5703 " stack_trace\t\t- Shows the max stack trace when active\n"
5704 " stack_max_size\t- Shows current max stack size that was traced\n"
5705 "\t\t\t Write into this file to reset the max size (trigger a\n"
5706 "\t\t\t new trace)\n"
5707#ifdef CONFIG_DYNAMIC_FTRACE
5708 " stack_trace_filter\t- Like set_ftrace_filter but limits what stack_trace\n"
5709 "\t\t\t traces\n"
5710#endif
5711#endif /* CONFIG_STACK_TRACER */
5712#ifdef CONFIG_DYNAMIC_EVENTS
5713 " dynamic_events\t\t- Create/append/remove/show the generic dynamic events\n"
5714 "\t\t\t Write into this file to define/undefine new trace events.\n"
5715#endif
5716#ifdef CONFIG_KPROBE_EVENTS
5717 " kprobe_events\t\t- Create/append/remove/show the kernel dynamic events\n"
5718 "\t\t\t Write into this file to define/undefine new trace events.\n"
5719#endif
5720#ifdef CONFIG_UPROBE_EVENTS
5721 " uprobe_events\t\t- Create/append/remove/show the userspace dynamic events\n"
5722 "\t\t\t Write into this file to define/undefine new trace events.\n"
5723#endif
5724#if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS) || \
5725 defined(CONFIG_FPROBE_EVENTS)
5726 "\t accepts: event-definitions (one definition per line)\n"
5727#if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS)
5728 "\t Format: p[:[<group>/][<event>]] <place> [<args>]\n"
5729 "\t r[maxactive][:[<group>/][<event>]] <place> [<args>]\n"
5730#endif
5731#ifdef CONFIG_FPROBE_EVENTS
5732 "\t f[:[<group>/][<event>]] <func-name>[%return] [<args>]\n"
5733 "\t t[:[<group>/][<event>]] <tracepoint> [<args>]\n"
5734#endif
5735#ifdef CONFIG_HIST_TRIGGERS
5736 "\t s:[synthetic/]<event> <field> [<field>]\n"
5737#endif
5738 "\t e[:[<group>/][<event>]] <attached-group>.<attached-event> [<args>] [if <filter>]\n"
5739 "\t -:[<group>/][<event>]\n"
5740#ifdef CONFIG_KPROBE_EVENTS
5741 "\t place: [<module>:]<symbol>[+<offset>]|<memaddr>\n"
5742 "place (kretprobe): [<module>:]<symbol>[+<offset>]%return|<memaddr>\n"
5743#endif
5744#ifdef CONFIG_UPROBE_EVENTS
5745 " place (uprobe): <path>:<offset>[%return][(ref_ctr_offset)]\n"
5746#endif
5747 "\t args: <name>=fetcharg[:type]\n"
5748 "\t fetcharg: (%<register>|$<efield>), @<address>, @<symbol>[+|-<offset>],\n"
5749#ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
5750#ifdef CONFIG_PROBE_EVENTS_BTF_ARGS
5751 "\t $stack<index>, $stack, $retval, $comm, $arg<N>,\n"
5752 "\t <argname>[->field[->field|.field...]],\n"
5753#else
5754 "\t $stack<index>, $stack, $retval, $comm, $arg<N>,\n"
5755#endif
5756#else
5757 "\t $stack<index>, $stack, $retval, $comm,\n"
5758#endif
5759 "\t +|-[u]<offset>(<fetcharg>), \\imm-value, \\\"imm-string\"\n"
5760 "\t type: s8/16/32/64, u8/16/32/64, x8/16/32/64, char, string, symbol,\n"
5761 "\t b<bit-width>@<bit-offset>/<container-size>, ustring,\n"
5762 "\t symstr, <type>\\[<array-size>\\]\n"
5763#ifdef CONFIG_HIST_TRIGGERS
5764 "\t field: <stype> <name>;\n"
5765 "\t stype: u8/u16/u32/u64, s8/s16/s32/s64, pid_t,\n"
5766 "\t [unsigned] char/int/long\n"
5767#endif
5768 "\t efield: For event probes ('e' types), the field is on of the fields\n"
5769 "\t of the <attached-group>/<attached-event>.\n"
5770#endif
5771 " events/\t\t- Directory containing all trace event subsystems:\n"
5772 " enable\t\t- Write 0/1 to enable/disable tracing of all events\n"
5773 " events/<system>/\t- Directory containing all trace events for <system>:\n"
5774 " enable\t\t- Write 0/1 to enable/disable tracing of all <system>\n"
5775 "\t\t\t events\n"
5776 " filter\t\t- If set, only events passing filter are traced\n"
5777 " events/<system>/<event>/\t- Directory containing control files for\n"
5778 "\t\t\t <event>:\n"
5779 " enable\t\t- Write 0/1 to enable/disable tracing of <event>\n"
5780 " filter\t\t- If set, only events passing filter are traced\n"
5781 " trigger\t\t- If set, a command to perform when event is hit\n"
5782 "\t Format: <trigger>[:count][if <filter>]\n"
5783 "\t trigger: traceon, traceoff\n"
5784 "\t enable_event:<system>:<event>\n"
5785 "\t disable_event:<system>:<event>\n"
5786#ifdef CONFIG_HIST_TRIGGERS
5787 "\t enable_hist:<system>:<event>\n"
5788 "\t disable_hist:<system>:<event>\n"
5789#endif
5790#ifdef CONFIG_STACKTRACE
5791 "\t\t stacktrace\n"
5792#endif
5793#ifdef CONFIG_TRACER_SNAPSHOT
5794 "\t\t snapshot\n"
5795#endif
5796#ifdef CONFIG_HIST_TRIGGERS
5797 "\t\t hist (see below)\n"
5798#endif
5799 "\t example: echo traceoff > events/block/block_unplug/trigger\n"
5800 "\t echo traceoff:3 > events/block/block_unplug/trigger\n"
5801 "\t echo 'enable_event:kmem:kmalloc:3 if nr_rq > 1' > \\\n"
5802 "\t events/block/block_unplug/trigger\n"
5803 "\t The first disables tracing every time block_unplug is hit.\n"
5804 "\t The second disables tracing the first 3 times block_unplug is hit.\n"
5805 "\t The third enables the kmalloc event the first 3 times block_unplug\n"
5806 "\t is hit and has value of greater than 1 for the 'nr_rq' event field.\n"
5807 "\t Like function triggers, the counter is only decremented if it\n"
5808 "\t enabled or disabled tracing.\n"
5809 "\t To remove a trigger without a count:\n"
5810 "\t echo '!<trigger> > <system>/<event>/trigger\n"
5811 "\t To remove a trigger with a count:\n"
5812 "\t echo '!<trigger>:0 > <system>/<event>/trigger\n"
5813 "\t Filters can be ignored when removing a trigger.\n"
5814#ifdef CONFIG_HIST_TRIGGERS
5815 " hist trigger\t- If set, event hits are aggregated into a hash table\n"
5816 "\t Format: hist:keys=<field1[,field2,...]>\n"
5817 "\t [:<var1>=<field|var_ref|numeric_literal>[,<var2>=...]]\n"
5818 "\t [:values=<field1[,field2,...]>]\n"
5819 "\t [:sort=<field1[,field2,...]>]\n"
5820 "\t [:size=#entries]\n"
5821 "\t [:pause][:continue][:clear]\n"
5822 "\t [:name=histname1]\n"
5823 "\t [:nohitcount]\n"
5824 "\t [:<handler>.<action>]\n"
5825 "\t [if <filter>]\n\n"
5826 "\t Note, special fields can be used as well:\n"
5827 "\t common_timestamp - to record current timestamp\n"
5828 "\t common_cpu - to record the CPU the event happened on\n"
5829 "\n"
5830 "\t A hist trigger variable can be:\n"
5831 "\t - a reference to a field e.g. x=current_timestamp,\n"
5832 "\t - a reference to another variable e.g. y=$x,\n"
5833 "\t - a numeric literal: e.g. ms_per_sec=1000,\n"
5834 "\t - an arithmetic expression: e.g. time_secs=current_timestamp/1000\n"
5835 "\n"
5836 "\t hist trigger arithmetic expressions support addition(+), subtraction(-),\n"
5837 "\t multiplication(*) and division(/) operators. An operand can be either a\n"
5838 "\t variable reference, field or numeric literal.\n"
5839 "\n"
5840 "\t When a matching event is hit, an entry is added to a hash\n"
5841 "\t table using the key(s) and value(s) named, and the value of a\n"
5842 "\t sum called 'hitcount' is incremented. Keys and values\n"
5843 "\t correspond to fields in the event's format description. Keys\n"
5844 "\t can be any field, or the special string 'common_stacktrace'.\n"
5845 "\t Compound keys consisting of up to two fields can be specified\n"
5846 "\t by the 'keys' keyword. Values must correspond to numeric\n"
5847 "\t fields. Sort keys consisting of up to two fields can be\n"
5848 "\t specified using the 'sort' keyword. The sort direction can\n"
5849 "\t be modified by appending '.descending' or '.ascending' to a\n"
5850 "\t sort field. The 'size' parameter can be used to specify more\n"
5851 "\t or fewer than the default 2048 entries for the hashtable size.\n"
5852 "\t If a hist trigger is given a name using the 'name' parameter,\n"
5853 "\t its histogram data will be shared with other triggers of the\n"
5854 "\t same name, and trigger hits will update this common data.\n\n"
5855 "\t Reading the 'hist' file for the event will dump the hash\n"
5856 "\t table in its entirety to stdout. If there are multiple hist\n"
5857 "\t triggers attached to an event, there will be a table for each\n"
5858 "\t trigger in the output. The table displayed for a named\n"
5859 "\t trigger will be the same as any other instance having the\n"
5860 "\t same name. The default format used to display a given field\n"
5861 "\t can be modified by appending any of the following modifiers\n"
5862 "\t to the field name, as applicable:\n\n"
5863 "\t .hex display a number as a hex value\n"
5864 "\t .sym display an address as a symbol\n"
5865 "\t .sym-offset display an address as a symbol and offset\n"
5866 "\t .execname display a common_pid as a program name\n"
5867 "\t .syscall display a syscall id as a syscall name\n"
5868 "\t .log2 display log2 value rather than raw number\n"
5869 "\t .buckets=size display values in groups of size rather than raw number\n"
5870 "\t .usecs display a common_timestamp in microseconds\n"
5871 "\t .percent display a number of percentage value\n"
5872 "\t .graph display a bar-graph of a value\n\n"
5873 "\t The 'pause' parameter can be used to pause an existing hist\n"
5874 "\t trigger or to start a hist trigger but not log any events\n"
5875 "\t until told to do so. 'continue' can be used to start or\n"
5876 "\t restart a paused hist trigger.\n\n"
5877 "\t The 'clear' parameter will clear the contents of a running\n"
5878 "\t hist trigger and leave its current paused/active state\n"
5879 "\t unchanged.\n\n"
5880 "\t The 'nohitcount' (or NOHC) parameter will suppress display of\n"
5881 "\t raw hitcount in the histogram.\n\n"
5882 "\t The enable_hist and disable_hist triggers can be used to\n"
5883 "\t have one event conditionally start and stop another event's\n"
5884 "\t already-attached hist trigger. The syntax is analogous to\n"
5885 "\t the enable_event and disable_event triggers.\n\n"
5886 "\t Hist trigger handlers and actions are executed whenever a\n"
5887 "\t a histogram entry is added or updated. They take the form:\n\n"
5888 "\t <handler>.<action>\n\n"
5889 "\t The available handlers are:\n\n"
5890 "\t onmatch(matching.event) - invoke on addition or update\n"
5891 "\t onmax(var) - invoke if var exceeds current max\n"
5892 "\t onchange(var) - invoke action if var changes\n\n"
5893 "\t The available actions are:\n\n"
5894 "\t trace(<synthetic_event>,param list) - generate synthetic event\n"
5895 "\t save(field,...) - save current event fields\n"
5896#ifdef CONFIG_TRACER_SNAPSHOT
5897 "\t snapshot() - snapshot the trace buffer\n\n"
5898#endif
5899#ifdef CONFIG_SYNTH_EVENTS
5900 " events/synthetic_events\t- Create/append/remove/show synthetic events\n"
5901 "\t Write into this file to define/undefine new synthetic events.\n"
5902 "\t example: echo 'myevent u64 lat; char name[]; long[] stack' >> synthetic_events\n"
5903#endif
5904#endif
5905;
5906
5907static ssize_t
5908tracing_readme_read(struct file *filp, char __user *ubuf,
5909 size_t cnt, loff_t *ppos)
5910{
5911 return simple_read_from_buffer(ubuf, cnt, ppos,
5912 readme_msg, strlen(readme_msg));
5913}
5914
5915static const struct file_operations tracing_readme_fops = {
5916 .open = tracing_open_generic,
5917 .read = tracing_readme_read,
5918 .llseek = generic_file_llseek,
5919};
5920
5921static void *saved_tgids_next(struct seq_file *m, void *v, loff_t *pos)
5922{
5923 int pid = ++(*pos);
5924
5925 return trace_find_tgid_ptr(pid);
5926}
5927
5928static void *saved_tgids_start(struct seq_file *m, loff_t *pos)
5929{
5930 int pid = *pos;
5931
5932 return trace_find_tgid_ptr(pid);
5933}
5934
5935static void saved_tgids_stop(struct seq_file *m, void *v)
5936{
5937}
5938
5939static int saved_tgids_show(struct seq_file *m, void *v)
5940{
5941 int *entry = (int *)v;
5942 int pid = entry - tgid_map;
5943 int tgid = *entry;
5944
5945 if (tgid == 0)
5946 return SEQ_SKIP;
5947
5948 seq_printf(m, "%d %d\n", pid, tgid);
5949 return 0;
5950}
5951
5952static const struct seq_operations tracing_saved_tgids_seq_ops = {
5953 .start = saved_tgids_start,
5954 .stop = saved_tgids_stop,
5955 .next = saved_tgids_next,
5956 .show = saved_tgids_show,
5957};
5958
5959static int tracing_saved_tgids_open(struct inode *inode, struct file *filp)
5960{
5961 int ret;
5962
5963 ret = tracing_check_open_get_tr(NULL);
5964 if (ret)
5965 return ret;
5966
5967 return seq_open(filp, &tracing_saved_tgids_seq_ops);
5968}
5969
5970
5971static const struct file_operations tracing_saved_tgids_fops = {
5972 .open = tracing_saved_tgids_open,
5973 .read = seq_read,
5974 .llseek = seq_lseek,
5975 .release = seq_release,
5976};
5977
5978static void *saved_cmdlines_next(struct seq_file *m, void *v, loff_t *pos)
5979{
5980 unsigned int *ptr = v;
5981
5982 if (*pos || m->count)
5983 ptr++;
5984
5985 (*pos)++;
5986
5987 for (; ptr < &savedcmd->map_cmdline_to_pid[savedcmd->cmdline_num];
5988 ptr++) {
5989 if (*ptr == -1 || *ptr == NO_CMDLINE_MAP)
5990 continue;
5991
5992 return ptr;
5993 }
5994
5995 return NULL;
5996}
5997
5998static void *saved_cmdlines_start(struct seq_file *m, loff_t *pos)
5999{
6000 void *v;
6001 loff_t l = 0;
6002
6003 preempt_disable();
6004 arch_spin_lock(&trace_cmdline_lock);
6005
6006 v = &savedcmd->map_cmdline_to_pid[0];
6007 while (l <= *pos) {
6008 v = saved_cmdlines_next(m, v, &l);
6009 if (!v)
6010 return NULL;
6011 }
6012
6013 return v;
6014}
6015
6016static void saved_cmdlines_stop(struct seq_file *m, void *v)
6017{
6018 arch_spin_unlock(&trace_cmdline_lock);
6019 preempt_enable();
6020}
6021
6022static int saved_cmdlines_show(struct seq_file *m, void *v)
6023{
6024 char buf[TASK_COMM_LEN];
6025 unsigned int *pid = v;
6026
6027 __trace_find_cmdline(*pid, buf);
6028 seq_printf(m, "%d %s\n", *pid, buf);
6029 return 0;
6030}
6031
6032static const struct seq_operations tracing_saved_cmdlines_seq_ops = {
6033 .start = saved_cmdlines_start,
6034 .next = saved_cmdlines_next,
6035 .stop = saved_cmdlines_stop,
6036 .show = saved_cmdlines_show,
6037};
6038
6039static int tracing_saved_cmdlines_open(struct inode *inode, struct file *filp)
6040{
6041 int ret;
6042
6043 ret = tracing_check_open_get_tr(NULL);
6044 if (ret)
6045 return ret;
6046
6047 return seq_open(filp, &tracing_saved_cmdlines_seq_ops);
6048}
6049
6050static const struct file_operations tracing_saved_cmdlines_fops = {
6051 .open = tracing_saved_cmdlines_open,
6052 .read = seq_read,
6053 .llseek = seq_lseek,
6054 .release = seq_release,
6055};
6056
6057static ssize_t
6058tracing_saved_cmdlines_size_read(struct file *filp, char __user *ubuf,
6059 size_t cnt, loff_t *ppos)
6060{
6061 char buf[64];
6062 int r;
6063
6064 preempt_disable();
6065 arch_spin_lock(&trace_cmdline_lock);
6066 r = scnprintf(buf, sizeof(buf), "%u\n", savedcmd->cmdline_num);
6067 arch_spin_unlock(&trace_cmdline_lock);
6068 preempt_enable();
6069
6070 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
6071}
6072
6073static int tracing_resize_saved_cmdlines(unsigned int val)
6074{
6075 struct saved_cmdlines_buffer *s, *savedcmd_temp;
6076
6077 s = allocate_cmdlines_buffer(val);
6078 if (!s)
6079 return -ENOMEM;
6080
6081 preempt_disable();
6082 arch_spin_lock(&trace_cmdline_lock);
6083 savedcmd_temp = savedcmd;
6084 savedcmd = s;
6085 arch_spin_unlock(&trace_cmdline_lock);
6086 preempt_enable();
6087 free_saved_cmdlines_buffer(savedcmd_temp);
6088
6089 return 0;
6090}
6091
6092static ssize_t
6093tracing_saved_cmdlines_size_write(struct file *filp, const char __user *ubuf,
6094 size_t cnt, loff_t *ppos)
6095{
6096 unsigned long val;
6097 int ret;
6098
6099 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
6100 if (ret)
6101 return ret;
6102
6103 /* must have at least 1 entry or less than PID_MAX_DEFAULT */
6104 if (!val || val > PID_MAX_DEFAULT)
6105 return -EINVAL;
6106
6107 ret = tracing_resize_saved_cmdlines((unsigned int)val);
6108 if (ret < 0)
6109 return ret;
6110
6111 *ppos += cnt;
6112
6113 return cnt;
6114}
6115
6116static const struct file_operations tracing_saved_cmdlines_size_fops = {
6117 .open = tracing_open_generic,
6118 .read = tracing_saved_cmdlines_size_read,
6119 .write = tracing_saved_cmdlines_size_write,
6120};
6121
6122#ifdef CONFIG_TRACE_EVAL_MAP_FILE
6123static union trace_eval_map_item *
6124update_eval_map(union trace_eval_map_item *ptr)
6125{
6126 if (!ptr->map.eval_string) {
6127 if (ptr->tail.next) {
6128 ptr = ptr->tail.next;
6129 /* Set ptr to the next real item (skip head) */
6130 ptr++;
6131 } else
6132 return NULL;
6133 }
6134 return ptr;
6135}
6136
6137static void *eval_map_next(struct seq_file *m, void *v, loff_t *pos)
6138{
6139 union trace_eval_map_item *ptr = v;
6140
6141 /*
6142 * Paranoid! If ptr points to end, we don't want to increment past it.
6143 * This really should never happen.
6144 */
6145 (*pos)++;
6146 ptr = update_eval_map(ptr);
6147 if (WARN_ON_ONCE(!ptr))
6148 return NULL;
6149
6150 ptr++;
6151 ptr = update_eval_map(ptr);
6152
6153 return ptr;
6154}
6155
6156static void *eval_map_start(struct seq_file *m, loff_t *pos)
6157{
6158 union trace_eval_map_item *v;
6159 loff_t l = 0;
6160
6161 mutex_lock(&trace_eval_mutex);
6162
6163 v = trace_eval_maps;
6164 if (v)
6165 v++;
6166
6167 while (v && l < *pos) {
6168 v = eval_map_next(m, v, &l);
6169 }
6170
6171 return v;
6172}
6173
6174static void eval_map_stop(struct seq_file *m, void *v)
6175{
6176 mutex_unlock(&trace_eval_mutex);
6177}
6178
6179static int eval_map_show(struct seq_file *m, void *v)
6180{
6181 union trace_eval_map_item *ptr = v;
6182
6183 seq_printf(m, "%s %ld (%s)\n",
6184 ptr->map.eval_string, ptr->map.eval_value,
6185 ptr->map.system);
6186
6187 return 0;
6188}
6189
6190static const struct seq_operations tracing_eval_map_seq_ops = {
6191 .start = eval_map_start,
6192 .next = eval_map_next,
6193 .stop = eval_map_stop,
6194 .show = eval_map_show,
6195};
6196
6197static int tracing_eval_map_open(struct inode *inode, struct file *filp)
6198{
6199 int ret;
6200
6201 ret = tracing_check_open_get_tr(NULL);
6202 if (ret)
6203 return ret;
6204
6205 return seq_open(filp, &tracing_eval_map_seq_ops);
6206}
6207
6208static const struct file_operations tracing_eval_map_fops = {
6209 .open = tracing_eval_map_open,
6210 .read = seq_read,
6211 .llseek = seq_lseek,
6212 .release = seq_release,
6213};
6214
6215static inline union trace_eval_map_item *
6216trace_eval_jmp_to_tail(union trace_eval_map_item *ptr)
6217{
6218 /* Return tail of array given the head */
6219 return ptr + ptr->head.length + 1;
6220}
6221
6222static void
6223trace_insert_eval_map_file(struct module *mod, struct trace_eval_map **start,
6224 int len)
6225{
6226 struct trace_eval_map **stop;
6227 struct trace_eval_map **map;
6228 union trace_eval_map_item *map_array;
6229 union trace_eval_map_item *ptr;
6230
6231 stop = start + len;
6232
6233 /*
6234 * The trace_eval_maps contains the map plus a head and tail item,
6235 * where the head holds the module and length of array, and the
6236 * tail holds a pointer to the next list.
6237 */
6238 map_array = kmalloc_array(len + 2, sizeof(*map_array), GFP_KERNEL);
6239 if (!map_array) {
6240 pr_warn("Unable to allocate trace eval mapping\n");
6241 return;
6242 }
6243
6244 mutex_lock(&trace_eval_mutex);
6245
6246 if (!trace_eval_maps)
6247 trace_eval_maps = map_array;
6248 else {
6249 ptr = trace_eval_maps;
6250 for (;;) {
6251 ptr = trace_eval_jmp_to_tail(ptr);
6252 if (!ptr->tail.next)
6253 break;
6254 ptr = ptr->tail.next;
6255
6256 }
6257 ptr->tail.next = map_array;
6258 }
6259 map_array->head.mod = mod;
6260 map_array->head.length = len;
6261 map_array++;
6262
6263 for (map = start; (unsigned long)map < (unsigned long)stop; map++) {
6264 map_array->map = **map;
6265 map_array++;
6266 }
6267 memset(map_array, 0, sizeof(*map_array));
6268
6269 mutex_unlock(&trace_eval_mutex);
6270}
6271
6272static void trace_create_eval_file(struct dentry *d_tracer)
6273{
6274 trace_create_file("eval_map", TRACE_MODE_READ, d_tracer,
6275 NULL, &tracing_eval_map_fops);
6276}
6277
6278#else /* CONFIG_TRACE_EVAL_MAP_FILE */
6279static inline void trace_create_eval_file(struct dentry *d_tracer) { }
6280static inline void trace_insert_eval_map_file(struct module *mod,
6281 struct trace_eval_map **start, int len) { }
6282#endif /* !CONFIG_TRACE_EVAL_MAP_FILE */
6283
6284static void trace_insert_eval_map(struct module *mod,
6285 struct trace_eval_map **start, int len)
6286{
6287 struct trace_eval_map **map;
6288
6289 if (len <= 0)
6290 return;
6291
6292 map = start;
6293
6294 trace_event_eval_update(map, len);
6295
6296 trace_insert_eval_map_file(mod, start, len);
6297}
6298
6299static ssize_t
6300tracing_set_trace_read(struct file *filp, char __user *ubuf,
6301 size_t cnt, loff_t *ppos)
6302{
6303 struct trace_array *tr = filp->private_data;
6304 char buf[MAX_TRACER_SIZE+2];
6305 int r;
6306
6307 mutex_lock(&trace_types_lock);
6308 r = sprintf(buf, "%s\n", tr->current_trace->name);
6309 mutex_unlock(&trace_types_lock);
6310
6311 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
6312}
6313
6314int tracer_init(struct tracer *t, struct trace_array *tr)
6315{
6316 tracing_reset_online_cpus(&tr->array_buffer);
6317 return t->init(tr);
6318}
6319
6320static void set_buffer_entries(struct array_buffer *buf, unsigned long val)
6321{
6322 int cpu;
6323
6324 for_each_tracing_cpu(cpu)
6325 per_cpu_ptr(buf->data, cpu)->entries = val;
6326}
6327
6328static void update_buffer_entries(struct array_buffer *buf, int cpu)
6329{
6330 if (cpu == RING_BUFFER_ALL_CPUS) {
6331 set_buffer_entries(buf, ring_buffer_size(buf->buffer, 0));
6332 } else {
6333 per_cpu_ptr(buf->data, cpu)->entries = ring_buffer_size(buf->buffer, cpu);
6334 }
6335}
6336
6337#ifdef CONFIG_TRACER_MAX_TRACE
6338/* resize @tr's buffer to the size of @size_tr's entries */
6339static int resize_buffer_duplicate_size(struct array_buffer *trace_buf,
6340 struct array_buffer *size_buf, int cpu_id)
6341{
6342 int cpu, ret = 0;
6343
6344 if (cpu_id == RING_BUFFER_ALL_CPUS) {
6345 for_each_tracing_cpu(cpu) {
6346 ret = ring_buffer_resize(trace_buf->buffer,
6347 per_cpu_ptr(size_buf->data, cpu)->entries, cpu);
6348 if (ret < 0)
6349 break;
6350 per_cpu_ptr(trace_buf->data, cpu)->entries =
6351 per_cpu_ptr(size_buf->data, cpu)->entries;
6352 }
6353 } else {
6354 ret = ring_buffer_resize(trace_buf->buffer,
6355 per_cpu_ptr(size_buf->data, cpu_id)->entries, cpu_id);
6356 if (ret == 0)
6357 per_cpu_ptr(trace_buf->data, cpu_id)->entries =
6358 per_cpu_ptr(size_buf->data, cpu_id)->entries;
6359 }
6360
6361 return ret;
6362}
6363#endif /* CONFIG_TRACER_MAX_TRACE */
6364
6365static int __tracing_resize_ring_buffer(struct trace_array *tr,
6366 unsigned long size, int cpu)
6367{
6368 int ret;
6369
6370 /*
6371 * If kernel or user changes the size of the ring buffer
6372 * we use the size that was given, and we can forget about
6373 * expanding it later.
6374 */
6375 trace_set_ring_buffer_expanded(tr);
6376
6377 /* May be called before buffers are initialized */
6378 if (!tr->array_buffer.buffer)
6379 return 0;
6380
6381 /* Do not allow tracing while resizing ring buffer */
6382 tracing_stop_tr(tr);
6383
6384 ret = ring_buffer_resize(tr->array_buffer.buffer, size, cpu);
6385 if (ret < 0)
6386 goto out_start;
6387
6388#ifdef CONFIG_TRACER_MAX_TRACE
6389 if (!tr->allocated_snapshot)
6390 goto out;
6391
6392 ret = ring_buffer_resize(tr->max_buffer.buffer, size, cpu);
6393 if (ret < 0) {
6394 int r = resize_buffer_duplicate_size(&tr->array_buffer,
6395 &tr->array_buffer, cpu);
6396 if (r < 0) {
6397 /*
6398 * AARGH! We are left with different
6399 * size max buffer!!!!
6400 * The max buffer is our "snapshot" buffer.
6401 * When a tracer needs a snapshot (one of the
6402 * latency tracers), it swaps the max buffer
6403 * with the saved snap shot. We succeeded to
6404 * update the size of the main buffer, but failed to
6405 * update the size of the max buffer. But when we tried
6406 * to reset the main buffer to the original size, we
6407 * failed there too. This is very unlikely to
6408 * happen, but if it does, warn and kill all
6409 * tracing.
6410 */
6411 WARN_ON(1);
6412 tracing_disabled = 1;
6413 }
6414 goto out_start;
6415 }
6416
6417 update_buffer_entries(&tr->max_buffer, cpu);
6418
6419 out:
6420#endif /* CONFIG_TRACER_MAX_TRACE */
6421
6422 update_buffer_entries(&tr->array_buffer, cpu);
6423 out_start:
6424 tracing_start_tr(tr);
6425 return ret;
6426}
6427
6428ssize_t tracing_resize_ring_buffer(struct trace_array *tr,
6429 unsigned long size, int cpu_id)
6430{
6431 int ret;
6432
6433 mutex_lock(&trace_types_lock);
6434
6435 if (cpu_id != RING_BUFFER_ALL_CPUS) {
6436 /* make sure, this cpu is enabled in the mask */
6437 if (!cpumask_test_cpu(cpu_id, tracing_buffer_mask)) {
6438 ret = -EINVAL;
6439 goto out;
6440 }
6441 }
6442
6443 ret = __tracing_resize_ring_buffer(tr, size, cpu_id);
6444 if (ret < 0)
6445 ret = -ENOMEM;
6446
6447out:
6448 mutex_unlock(&trace_types_lock);
6449
6450 return ret;
6451}
6452
6453
6454/**
6455 * tracing_update_buffers - used by tracing facility to expand ring buffers
6456 * @tr: The tracing instance
6457 *
6458 * To save on memory when the tracing is never used on a system with it
6459 * configured in. The ring buffers are set to a minimum size. But once
6460 * a user starts to use the tracing facility, then they need to grow
6461 * to their default size.
6462 *
6463 * This function is to be called when a tracer is about to be used.
6464 */
6465int tracing_update_buffers(struct trace_array *tr)
6466{
6467 int ret = 0;
6468
6469 mutex_lock(&trace_types_lock);
6470 if (!tr->ring_buffer_expanded)
6471 ret = __tracing_resize_ring_buffer(tr, trace_buf_size,
6472 RING_BUFFER_ALL_CPUS);
6473 mutex_unlock(&trace_types_lock);
6474
6475 return ret;
6476}
6477
6478struct trace_option_dentry;
6479
6480static void
6481create_trace_option_files(struct trace_array *tr, struct tracer *tracer);
6482
6483/*
6484 * Used to clear out the tracer before deletion of an instance.
6485 * Must have trace_types_lock held.
6486 */
6487static void tracing_set_nop(struct trace_array *tr)
6488{
6489 if (tr->current_trace == &nop_trace)
6490 return;
6491
6492 tr->current_trace->enabled--;
6493
6494 if (tr->current_trace->reset)
6495 tr->current_trace->reset(tr);
6496
6497 tr->current_trace = &nop_trace;
6498}
6499
6500static bool tracer_options_updated;
6501
6502static void add_tracer_options(struct trace_array *tr, struct tracer *t)
6503{
6504 /* Only enable if the directory has been created already. */
6505 if (!tr->dir)
6506 return;
6507
6508 /* Only create trace option files after update_tracer_options finish */
6509 if (!tracer_options_updated)
6510 return;
6511
6512 create_trace_option_files(tr, t);
6513}
6514
6515int tracing_set_tracer(struct trace_array *tr, const char *buf)
6516{
6517 struct tracer *t;
6518#ifdef CONFIG_TRACER_MAX_TRACE
6519 bool had_max_tr;
6520#endif
6521 int ret = 0;
6522
6523 mutex_lock(&trace_types_lock);
6524
6525 if (!tr->ring_buffer_expanded) {
6526 ret = __tracing_resize_ring_buffer(tr, trace_buf_size,
6527 RING_BUFFER_ALL_CPUS);
6528 if (ret < 0)
6529 goto out;
6530 ret = 0;
6531 }
6532
6533 for (t = trace_types; t; t = t->next) {
6534 if (strcmp(t->name, buf) == 0)
6535 break;
6536 }
6537 if (!t) {
6538 ret = -EINVAL;
6539 goto out;
6540 }
6541 if (t == tr->current_trace)
6542 goto out;
6543
6544#ifdef CONFIG_TRACER_SNAPSHOT
6545 if (t->use_max_tr) {
6546 local_irq_disable();
6547 arch_spin_lock(&tr->max_lock);
6548 if (tr->cond_snapshot)
6549 ret = -EBUSY;
6550 arch_spin_unlock(&tr->max_lock);
6551 local_irq_enable();
6552 if (ret)
6553 goto out;
6554 }
6555#endif
6556 /* Some tracers won't work on kernel command line */
6557 if (system_state < SYSTEM_RUNNING && t->noboot) {
6558 pr_warn("Tracer '%s' is not allowed on command line, ignored\n",
6559 t->name);
6560 goto out;
6561 }
6562
6563 /* Some tracers are only allowed for the top level buffer */
6564 if (!trace_ok_for_array(t, tr)) {
6565 ret = -EINVAL;
6566 goto out;
6567 }
6568
6569 /* If trace pipe files are being read, we can't change the tracer */
6570 if (tr->trace_ref) {
6571 ret = -EBUSY;
6572 goto out;
6573 }
6574
6575 trace_branch_disable();
6576
6577 tr->current_trace->enabled--;
6578
6579 if (tr->current_trace->reset)
6580 tr->current_trace->reset(tr);
6581
6582#ifdef CONFIG_TRACER_MAX_TRACE
6583 had_max_tr = tr->current_trace->use_max_tr;
6584
6585 /* Current trace needs to be nop_trace before synchronize_rcu */
6586 tr->current_trace = &nop_trace;
6587
6588 if (had_max_tr && !t->use_max_tr) {
6589 /*
6590 * We need to make sure that the update_max_tr sees that
6591 * current_trace changed to nop_trace to keep it from
6592 * swapping the buffers after we resize it.
6593 * The update_max_tr is called from interrupts disabled
6594 * so a synchronized_sched() is sufficient.
6595 */
6596 synchronize_rcu();
6597 free_snapshot(tr);
6598 }
6599
6600 if (t->use_max_tr && !tr->allocated_snapshot) {
6601 ret = tracing_alloc_snapshot_instance(tr);
6602 if (ret < 0)
6603 goto out;
6604 }
6605#else
6606 tr->current_trace = &nop_trace;
6607#endif
6608
6609 if (t->init) {
6610 ret = tracer_init(t, tr);
6611 if (ret)
6612 goto out;
6613 }
6614
6615 tr->current_trace = t;
6616 tr->current_trace->enabled++;
6617 trace_branch_enable(tr);
6618 out:
6619 mutex_unlock(&trace_types_lock);
6620
6621 return ret;
6622}
6623
6624static ssize_t
6625tracing_set_trace_write(struct file *filp, const char __user *ubuf,
6626 size_t cnt, loff_t *ppos)
6627{
6628 struct trace_array *tr = filp->private_data;
6629 char buf[MAX_TRACER_SIZE+1];
6630 char *name;
6631 size_t ret;
6632 int err;
6633
6634 ret = cnt;
6635
6636 if (cnt > MAX_TRACER_SIZE)
6637 cnt = MAX_TRACER_SIZE;
6638
6639 if (copy_from_user(buf, ubuf, cnt))
6640 return -EFAULT;
6641
6642 buf[cnt] = 0;
6643
6644 name = strim(buf);
6645
6646 err = tracing_set_tracer(tr, name);
6647 if (err)
6648 return err;
6649
6650 *ppos += ret;
6651
6652 return ret;
6653}
6654
6655static ssize_t
6656tracing_nsecs_read(unsigned long *ptr, char __user *ubuf,
6657 size_t cnt, loff_t *ppos)
6658{
6659 char buf[64];
6660 int r;
6661
6662 r = snprintf(buf, sizeof(buf), "%ld\n",
6663 *ptr == (unsigned long)-1 ? -1 : nsecs_to_usecs(*ptr));
6664 if (r > sizeof(buf))
6665 r = sizeof(buf);
6666 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
6667}
6668
6669static ssize_t
6670tracing_nsecs_write(unsigned long *ptr, const char __user *ubuf,
6671 size_t cnt, loff_t *ppos)
6672{
6673 unsigned long val;
6674 int ret;
6675
6676 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
6677 if (ret)
6678 return ret;
6679
6680 *ptr = val * 1000;
6681
6682 return cnt;
6683}
6684
6685static ssize_t
6686tracing_thresh_read(struct file *filp, char __user *ubuf,
6687 size_t cnt, loff_t *ppos)
6688{
6689 return tracing_nsecs_read(&tracing_thresh, ubuf, cnt, ppos);
6690}
6691
6692static ssize_t
6693tracing_thresh_write(struct file *filp, const char __user *ubuf,
6694 size_t cnt, loff_t *ppos)
6695{
6696 struct trace_array *tr = filp->private_data;
6697 int ret;
6698
6699 mutex_lock(&trace_types_lock);
6700 ret = tracing_nsecs_write(&tracing_thresh, ubuf, cnt, ppos);
6701 if (ret < 0)
6702 goto out;
6703
6704 if (tr->current_trace->update_thresh) {
6705 ret = tr->current_trace->update_thresh(tr);
6706 if (ret < 0)
6707 goto out;
6708 }
6709
6710 ret = cnt;
6711out:
6712 mutex_unlock(&trace_types_lock);
6713
6714 return ret;
6715}
6716
6717#ifdef CONFIG_TRACER_MAX_TRACE
6718
6719static ssize_t
6720tracing_max_lat_read(struct file *filp, char __user *ubuf,
6721 size_t cnt, loff_t *ppos)
6722{
6723 struct trace_array *tr = filp->private_data;
6724
6725 return tracing_nsecs_read(&tr->max_latency, ubuf, cnt, ppos);
6726}
6727
6728static ssize_t
6729tracing_max_lat_write(struct file *filp, const char __user *ubuf,
6730 size_t cnt, loff_t *ppos)
6731{
6732 struct trace_array *tr = filp->private_data;
6733
6734 return tracing_nsecs_write(&tr->max_latency, ubuf, cnt, ppos);
6735}
6736
6737#endif
6738
6739static int open_pipe_on_cpu(struct trace_array *tr, int cpu)
6740{
6741 if (cpu == RING_BUFFER_ALL_CPUS) {
6742 if (cpumask_empty(tr->pipe_cpumask)) {
6743 cpumask_setall(tr->pipe_cpumask);
6744 return 0;
6745 }
6746 } else if (!cpumask_test_cpu(cpu, tr->pipe_cpumask)) {
6747 cpumask_set_cpu(cpu, tr->pipe_cpumask);
6748 return 0;
6749 }
6750 return -EBUSY;
6751}
6752
6753static void close_pipe_on_cpu(struct trace_array *tr, int cpu)
6754{
6755 if (cpu == RING_BUFFER_ALL_CPUS) {
6756 WARN_ON(!cpumask_full(tr->pipe_cpumask));
6757 cpumask_clear(tr->pipe_cpumask);
6758 } else {
6759 WARN_ON(!cpumask_test_cpu(cpu, tr->pipe_cpumask));
6760 cpumask_clear_cpu(cpu, tr->pipe_cpumask);
6761 }
6762}
6763
6764static int tracing_open_pipe(struct inode *inode, struct file *filp)
6765{
6766 struct trace_array *tr = inode->i_private;
6767 struct trace_iterator *iter;
6768 int cpu;
6769 int ret;
6770
6771 ret = tracing_check_open_get_tr(tr);
6772 if (ret)
6773 return ret;
6774
6775 mutex_lock(&trace_types_lock);
6776 cpu = tracing_get_cpu(inode);
6777 ret = open_pipe_on_cpu(tr, cpu);
6778 if (ret)
6779 goto fail_pipe_on_cpu;
6780
6781 /* create a buffer to store the information to pass to userspace */
6782 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
6783 if (!iter) {
6784 ret = -ENOMEM;
6785 goto fail_alloc_iter;
6786 }
6787
6788 trace_seq_init(&iter->seq);
6789 iter->trace = tr->current_trace;
6790
6791 if (!alloc_cpumask_var(&iter->started, GFP_KERNEL)) {
6792 ret = -ENOMEM;
6793 goto fail;
6794 }
6795
6796 /* trace pipe does not show start of buffer */
6797 cpumask_setall(iter->started);
6798
6799 if (tr->trace_flags & TRACE_ITER_LATENCY_FMT)
6800 iter->iter_flags |= TRACE_FILE_LAT_FMT;
6801
6802 /* Output in nanoseconds only if we are using a clock in nanoseconds. */
6803 if (trace_clocks[tr->clock_id].in_ns)
6804 iter->iter_flags |= TRACE_FILE_TIME_IN_NS;
6805
6806 iter->tr = tr;
6807 iter->array_buffer = &tr->array_buffer;
6808 iter->cpu_file = cpu;
6809 mutex_init(&iter->mutex);
6810 filp->private_data = iter;
6811
6812 if (iter->trace->pipe_open)
6813 iter->trace->pipe_open(iter);
6814
6815 nonseekable_open(inode, filp);
6816
6817 tr->trace_ref++;
6818
6819 mutex_unlock(&trace_types_lock);
6820 return ret;
6821
6822fail:
6823 kfree(iter);
6824fail_alloc_iter:
6825 close_pipe_on_cpu(tr, cpu);
6826fail_pipe_on_cpu:
6827 __trace_array_put(tr);
6828 mutex_unlock(&trace_types_lock);
6829 return ret;
6830}
6831
6832static int tracing_release_pipe(struct inode *inode, struct file *file)
6833{
6834 struct trace_iterator *iter = file->private_data;
6835 struct trace_array *tr = inode->i_private;
6836
6837 mutex_lock(&trace_types_lock);
6838
6839 tr->trace_ref--;
6840
6841 if (iter->trace->pipe_close)
6842 iter->trace->pipe_close(iter);
6843 close_pipe_on_cpu(tr, iter->cpu_file);
6844 mutex_unlock(&trace_types_lock);
6845
6846 free_trace_iter_content(iter);
6847 kfree(iter);
6848
6849 trace_array_put(tr);
6850
6851 return 0;
6852}
6853
6854static __poll_t
6855trace_poll(struct trace_iterator *iter, struct file *filp, poll_table *poll_table)
6856{
6857 struct trace_array *tr = iter->tr;
6858
6859 /* Iterators are static, they should be filled or empty */
6860 if (trace_buffer_iter(iter, iter->cpu_file))
6861 return EPOLLIN | EPOLLRDNORM;
6862
6863 if (tr->trace_flags & TRACE_ITER_BLOCK)
6864 /*
6865 * Always select as readable when in blocking mode
6866 */
6867 return EPOLLIN | EPOLLRDNORM;
6868 else
6869 return ring_buffer_poll_wait(iter->array_buffer->buffer, iter->cpu_file,
6870 filp, poll_table, iter->tr->buffer_percent);
6871}
6872
6873static __poll_t
6874tracing_poll_pipe(struct file *filp, poll_table *poll_table)
6875{
6876 struct trace_iterator *iter = filp->private_data;
6877
6878 return trace_poll(iter, filp, poll_table);
6879}
6880
6881/* Must be called with iter->mutex held. */
6882static int tracing_wait_pipe(struct file *filp)
6883{
6884 struct trace_iterator *iter = filp->private_data;
6885 int ret;
6886
6887 while (trace_empty(iter)) {
6888
6889 if ((filp->f_flags & O_NONBLOCK)) {
6890 return -EAGAIN;
6891 }
6892
6893 /*
6894 * We block until we read something and tracing is disabled.
6895 * We still block if tracing is disabled, but we have never
6896 * read anything. This allows a user to cat this file, and
6897 * then enable tracing. But after we have read something,
6898 * we give an EOF when tracing is again disabled.
6899 *
6900 * iter->pos will be 0 if we haven't read anything.
6901 */
6902 if (!tracer_tracing_is_on(iter->tr) && iter->pos)
6903 break;
6904
6905 mutex_unlock(&iter->mutex);
6906
6907 ret = wait_on_pipe(iter, 0);
6908
6909 mutex_lock(&iter->mutex);
6910
6911 if (ret)
6912 return ret;
6913 }
6914
6915 return 1;
6916}
6917
6918/*
6919 * Consumer reader.
6920 */
6921static ssize_t
6922tracing_read_pipe(struct file *filp, char __user *ubuf,
6923 size_t cnt, loff_t *ppos)
6924{
6925 struct trace_iterator *iter = filp->private_data;
6926 ssize_t sret;
6927
6928 /*
6929 * Avoid more than one consumer on a single file descriptor
6930 * This is just a matter of traces coherency, the ring buffer itself
6931 * is protected.
6932 */
6933 mutex_lock(&iter->mutex);
6934
6935 /* return any leftover data */
6936 sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
6937 if (sret != -EBUSY)
6938 goto out;
6939
6940 trace_seq_init(&iter->seq);
6941
6942 if (iter->trace->read) {
6943 sret = iter->trace->read(iter, filp, ubuf, cnt, ppos);
6944 if (sret)
6945 goto out;
6946 }
6947
6948waitagain:
6949 sret = tracing_wait_pipe(filp);
6950 if (sret <= 0)
6951 goto out;
6952
6953 /* stop when tracing is finished */
6954 if (trace_empty(iter)) {
6955 sret = 0;
6956 goto out;
6957 }
6958
6959 if (cnt >= TRACE_SEQ_BUFFER_SIZE)
6960 cnt = TRACE_SEQ_BUFFER_SIZE - 1;
6961
6962 /* reset all but tr, trace, and overruns */
6963 trace_iterator_reset(iter);
6964 cpumask_clear(iter->started);
6965 trace_seq_init(&iter->seq);
6966
6967 trace_event_read_lock();
6968 trace_access_lock(iter->cpu_file);
6969 while (trace_find_next_entry_inc(iter) != NULL) {
6970 enum print_line_t ret;
6971 int save_len = iter->seq.seq.len;
6972
6973 ret = print_trace_line(iter);
6974 if (ret == TRACE_TYPE_PARTIAL_LINE) {
6975 /*
6976 * If one print_trace_line() fills entire trace_seq in one shot,
6977 * trace_seq_to_user() will returns -EBUSY because save_len == 0,
6978 * In this case, we need to consume it, otherwise, loop will peek
6979 * this event next time, resulting in an infinite loop.
6980 */
6981 if (save_len == 0) {
6982 iter->seq.full = 0;
6983 trace_seq_puts(&iter->seq, "[LINE TOO BIG]\n");
6984 trace_consume(iter);
6985 break;
6986 }
6987
6988 /* In other cases, don't print partial lines */
6989 iter->seq.seq.len = save_len;
6990 break;
6991 }
6992 if (ret != TRACE_TYPE_NO_CONSUME)
6993 trace_consume(iter);
6994
6995 if (trace_seq_used(&iter->seq) >= cnt)
6996 break;
6997
6998 /*
6999 * Setting the full flag means we reached the trace_seq buffer
7000 * size and we should leave by partial output condition above.
7001 * One of the trace_seq_* functions is not used properly.
7002 */
7003 WARN_ONCE(iter->seq.full, "full flag set for trace type %d",
7004 iter->ent->type);
7005 }
7006 trace_access_unlock(iter->cpu_file);
7007 trace_event_read_unlock();
7008
7009 /* Now copy what we have to the user */
7010 sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
7011 if (iter->seq.readpos >= trace_seq_used(&iter->seq))
7012 trace_seq_init(&iter->seq);
7013
7014 /*
7015 * If there was nothing to send to user, in spite of consuming trace
7016 * entries, go back to wait for more entries.
7017 */
7018 if (sret == -EBUSY)
7019 goto waitagain;
7020
7021out:
7022 mutex_unlock(&iter->mutex);
7023
7024 return sret;
7025}
7026
7027static void tracing_spd_release_pipe(struct splice_pipe_desc *spd,
7028 unsigned int idx)
7029{
7030 __free_page(spd->pages[idx]);
7031}
7032
7033static size_t
7034tracing_fill_pipe_page(size_t rem, struct trace_iterator *iter)
7035{
7036 size_t count;
7037 int save_len;
7038 int ret;
7039
7040 /* Seq buffer is page-sized, exactly what we need. */
7041 for (;;) {
7042 save_len = iter->seq.seq.len;
7043 ret = print_trace_line(iter);
7044
7045 if (trace_seq_has_overflowed(&iter->seq)) {
7046 iter->seq.seq.len = save_len;
7047 break;
7048 }
7049
7050 /*
7051 * This should not be hit, because it should only
7052 * be set if the iter->seq overflowed. But check it
7053 * anyway to be safe.
7054 */
7055 if (ret == TRACE_TYPE_PARTIAL_LINE) {
7056 iter->seq.seq.len = save_len;
7057 break;
7058 }
7059
7060 count = trace_seq_used(&iter->seq) - save_len;
7061 if (rem < count) {
7062 rem = 0;
7063 iter->seq.seq.len = save_len;
7064 break;
7065 }
7066
7067 if (ret != TRACE_TYPE_NO_CONSUME)
7068 trace_consume(iter);
7069 rem -= count;
7070 if (!trace_find_next_entry_inc(iter)) {
7071 rem = 0;
7072 iter->ent = NULL;
7073 break;
7074 }
7075 }
7076
7077 return rem;
7078}
7079
7080static ssize_t tracing_splice_read_pipe(struct file *filp,
7081 loff_t *ppos,
7082 struct pipe_inode_info *pipe,
7083 size_t len,
7084 unsigned int flags)
7085{
7086 struct page *pages_def[PIPE_DEF_BUFFERS];
7087 struct partial_page partial_def[PIPE_DEF_BUFFERS];
7088 struct trace_iterator *iter = filp->private_data;
7089 struct splice_pipe_desc spd = {
7090 .pages = pages_def,
7091 .partial = partial_def,
7092 .nr_pages = 0, /* This gets updated below. */
7093 .nr_pages_max = PIPE_DEF_BUFFERS,
7094 .ops = &default_pipe_buf_ops,
7095 .spd_release = tracing_spd_release_pipe,
7096 };
7097 ssize_t ret;
7098 size_t rem;
7099 unsigned int i;
7100
7101 if (splice_grow_spd(pipe, &spd))
7102 return -ENOMEM;
7103
7104 mutex_lock(&iter->mutex);
7105
7106 if (iter->trace->splice_read) {
7107 ret = iter->trace->splice_read(iter, filp,
7108 ppos, pipe, len, flags);
7109 if (ret)
7110 goto out_err;
7111 }
7112
7113 ret = tracing_wait_pipe(filp);
7114 if (ret <= 0)
7115 goto out_err;
7116
7117 if (!iter->ent && !trace_find_next_entry_inc(iter)) {
7118 ret = -EFAULT;
7119 goto out_err;
7120 }
7121
7122 trace_event_read_lock();
7123 trace_access_lock(iter->cpu_file);
7124
7125 /* Fill as many pages as possible. */
7126 for (i = 0, rem = len; i < spd.nr_pages_max && rem; i++) {
7127 spd.pages[i] = alloc_page(GFP_KERNEL);
7128 if (!spd.pages[i])
7129 break;
7130
7131 rem = tracing_fill_pipe_page(rem, iter);
7132
7133 /* Copy the data into the page, so we can start over. */
7134 ret = trace_seq_to_buffer(&iter->seq,
7135 page_address(spd.pages[i]),
7136 trace_seq_used(&iter->seq));
7137 if (ret < 0) {
7138 __free_page(spd.pages[i]);
7139 break;
7140 }
7141 spd.partial[i].offset = 0;
7142 spd.partial[i].len = trace_seq_used(&iter->seq);
7143
7144 trace_seq_init(&iter->seq);
7145 }
7146
7147 trace_access_unlock(iter->cpu_file);
7148 trace_event_read_unlock();
7149 mutex_unlock(&iter->mutex);
7150
7151 spd.nr_pages = i;
7152
7153 if (i)
7154 ret = splice_to_pipe(pipe, &spd);
7155 else
7156 ret = 0;
7157out:
7158 splice_shrink_spd(&spd);
7159 return ret;
7160
7161out_err:
7162 mutex_unlock(&iter->mutex);
7163 goto out;
7164}
7165
7166static ssize_t
7167tracing_entries_read(struct file *filp, char __user *ubuf,
7168 size_t cnt, loff_t *ppos)
7169{
7170 struct inode *inode = file_inode(filp);
7171 struct trace_array *tr = inode->i_private;
7172 int cpu = tracing_get_cpu(inode);
7173 char buf[64];
7174 int r = 0;
7175 ssize_t ret;
7176
7177 mutex_lock(&trace_types_lock);
7178
7179 if (cpu == RING_BUFFER_ALL_CPUS) {
7180 int cpu, buf_size_same;
7181 unsigned long size;
7182
7183 size = 0;
7184 buf_size_same = 1;
7185 /* check if all cpu sizes are same */
7186 for_each_tracing_cpu(cpu) {
7187 /* fill in the size from first enabled cpu */
7188 if (size == 0)
7189 size = per_cpu_ptr(tr->array_buffer.data, cpu)->entries;
7190 if (size != per_cpu_ptr(tr->array_buffer.data, cpu)->entries) {
7191 buf_size_same = 0;
7192 break;
7193 }
7194 }
7195
7196 if (buf_size_same) {
7197 if (!tr->ring_buffer_expanded)
7198 r = sprintf(buf, "%lu (expanded: %lu)\n",
7199 size >> 10,
7200 trace_buf_size >> 10);
7201 else
7202 r = sprintf(buf, "%lu\n", size >> 10);
7203 } else
7204 r = sprintf(buf, "X\n");
7205 } else
7206 r = sprintf(buf, "%lu\n", per_cpu_ptr(tr->array_buffer.data, cpu)->entries >> 10);
7207
7208 mutex_unlock(&trace_types_lock);
7209
7210 ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
7211 return ret;
7212}
7213
7214static ssize_t
7215tracing_entries_write(struct file *filp, const char __user *ubuf,
7216 size_t cnt, loff_t *ppos)
7217{
7218 struct inode *inode = file_inode(filp);
7219 struct trace_array *tr = inode->i_private;
7220 unsigned long val;
7221 int ret;
7222
7223 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
7224 if (ret)
7225 return ret;
7226
7227 /* must have at least 1 entry */
7228 if (!val)
7229 return -EINVAL;
7230
7231 /* value is in KB */
7232 val <<= 10;
7233 ret = tracing_resize_ring_buffer(tr, val, tracing_get_cpu(inode));
7234 if (ret < 0)
7235 return ret;
7236
7237 *ppos += cnt;
7238
7239 return cnt;
7240}
7241
7242static ssize_t
7243tracing_total_entries_read(struct file *filp, char __user *ubuf,
7244 size_t cnt, loff_t *ppos)
7245{
7246 struct trace_array *tr = filp->private_data;
7247 char buf[64];
7248 int r, cpu;
7249 unsigned long size = 0, expanded_size = 0;
7250
7251 mutex_lock(&trace_types_lock);
7252 for_each_tracing_cpu(cpu) {
7253 size += per_cpu_ptr(tr->array_buffer.data, cpu)->entries >> 10;
7254 if (!tr->ring_buffer_expanded)
7255 expanded_size += trace_buf_size >> 10;
7256 }
7257 if (tr->ring_buffer_expanded)
7258 r = sprintf(buf, "%lu\n", size);
7259 else
7260 r = sprintf(buf, "%lu (expanded: %lu)\n", size, expanded_size);
7261 mutex_unlock(&trace_types_lock);
7262
7263 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
7264}
7265
7266static ssize_t
7267tracing_free_buffer_write(struct file *filp, const char __user *ubuf,
7268 size_t cnt, loff_t *ppos)
7269{
7270 /*
7271 * There is no need to read what the user has written, this function
7272 * is just to make sure that there is no error when "echo" is used
7273 */
7274
7275 *ppos += cnt;
7276
7277 return cnt;
7278}
7279
7280static int
7281tracing_free_buffer_release(struct inode *inode, struct file *filp)
7282{
7283 struct trace_array *tr = inode->i_private;
7284
7285 /* disable tracing ? */
7286 if (tr->trace_flags & TRACE_ITER_STOP_ON_FREE)
7287 tracer_tracing_off(tr);
7288 /* resize the ring buffer to 0 */
7289 tracing_resize_ring_buffer(tr, 0, RING_BUFFER_ALL_CPUS);
7290
7291 trace_array_put(tr);
7292
7293 return 0;
7294}
7295
7296#define TRACE_MARKER_MAX_SIZE 4096
7297
7298static ssize_t
7299tracing_mark_write(struct file *filp, const char __user *ubuf,
7300 size_t cnt, loff_t *fpos)
7301{
7302 struct trace_array *tr = filp->private_data;
7303 struct ring_buffer_event *event;
7304 enum event_trigger_type tt = ETT_NONE;
7305 struct trace_buffer *buffer;
7306 struct print_entry *entry;
7307 int meta_size;
7308 ssize_t written;
7309 size_t size;
7310 int len;
7311
7312/* Used in tracing_mark_raw_write() as well */
7313#define FAULTED_STR "<faulted>"
7314#define FAULTED_SIZE (sizeof(FAULTED_STR) - 1) /* '\0' is already accounted for */
7315
7316 if (tracing_disabled)
7317 return -EINVAL;
7318
7319 if (!(tr->trace_flags & TRACE_ITER_MARKERS))
7320 return -EINVAL;
7321
7322 if ((ssize_t)cnt < 0)
7323 return -EINVAL;
7324
7325 if (cnt > TRACE_MARKER_MAX_SIZE)
7326 cnt = TRACE_MARKER_MAX_SIZE;
7327
7328 meta_size = sizeof(*entry) + 2; /* add '\0' and possible '\n' */
7329 again:
7330 size = cnt + meta_size;
7331
7332 /* If less than "<faulted>", then make sure we can still add that */
7333 if (cnt < FAULTED_SIZE)
7334 size += FAULTED_SIZE - cnt;
7335
7336 buffer = tr->array_buffer.buffer;
7337 event = __trace_buffer_lock_reserve(buffer, TRACE_PRINT, size,
7338 tracing_gen_ctx());
7339 if (unlikely(!event)) {
7340 /*
7341 * If the size was greater than what was allowed, then
7342 * make it smaller and try again.
7343 */
7344 if (size > ring_buffer_max_event_size(buffer)) {
7345 /* cnt < FAULTED size should never be bigger than max */
7346 if (WARN_ON_ONCE(cnt < FAULTED_SIZE))
7347 return -EBADF;
7348 cnt = ring_buffer_max_event_size(buffer) - meta_size;
7349 /* The above should only happen once */
7350 if (WARN_ON_ONCE(cnt + meta_size == size))
7351 return -EBADF;
7352 goto again;
7353 }
7354
7355 /* Ring buffer disabled, return as if not open for write */
7356 return -EBADF;
7357 }
7358
7359 entry = ring_buffer_event_data(event);
7360 entry->ip = _THIS_IP_;
7361
7362 len = __copy_from_user_inatomic(&entry->buf, ubuf, cnt);
7363 if (len) {
7364 memcpy(&entry->buf, FAULTED_STR, FAULTED_SIZE);
7365 cnt = FAULTED_SIZE;
7366 written = -EFAULT;
7367 } else
7368 written = cnt;
7369
7370 if (tr->trace_marker_file && !list_empty(&tr->trace_marker_file->triggers)) {
7371 /* do not add \n before testing triggers, but add \0 */
7372 entry->buf[cnt] = '\0';
7373 tt = event_triggers_call(tr->trace_marker_file, buffer, entry, event);
7374 }
7375
7376 if (entry->buf[cnt - 1] != '\n') {
7377 entry->buf[cnt] = '\n';
7378 entry->buf[cnt + 1] = '\0';
7379 } else
7380 entry->buf[cnt] = '\0';
7381
7382 if (static_branch_unlikely(&trace_marker_exports_enabled))
7383 ftrace_exports(event, TRACE_EXPORT_MARKER);
7384 __buffer_unlock_commit(buffer, event);
7385
7386 if (tt)
7387 event_triggers_post_call(tr->trace_marker_file, tt);
7388
7389 return written;
7390}
7391
7392static ssize_t
7393tracing_mark_raw_write(struct file *filp, const char __user *ubuf,
7394 size_t cnt, loff_t *fpos)
7395{
7396 struct trace_array *tr = filp->private_data;
7397 struct ring_buffer_event *event;
7398 struct trace_buffer *buffer;
7399 struct raw_data_entry *entry;
7400 ssize_t written;
7401 int size;
7402 int len;
7403
7404#define FAULT_SIZE_ID (FAULTED_SIZE + sizeof(int))
7405
7406 if (tracing_disabled)
7407 return -EINVAL;
7408
7409 if (!(tr->trace_flags & TRACE_ITER_MARKERS))
7410 return -EINVAL;
7411
7412 /* The marker must at least have a tag id */
7413 if (cnt < sizeof(unsigned int))
7414 return -EINVAL;
7415
7416 size = sizeof(*entry) + cnt;
7417 if (cnt < FAULT_SIZE_ID)
7418 size += FAULT_SIZE_ID - cnt;
7419
7420 buffer = tr->array_buffer.buffer;
7421
7422 if (size > ring_buffer_max_event_size(buffer))
7423 return -EINVAL;
7424
7425 event = __trace_buffer_lock_reserve(buffer, TRACE_RAW_DATA, size,
7426 tracing_gen_ctx());
7427 if (!event)
7428 /* Ring buffer disabled, return as if not open for write */
7429 return -EBADF;
7430
7431 entry = ring_buffer_event_data(event);
7432
7433 len = __copy_from_user_inatomic(&entry->id, ubuf, cnt);
7434 if (len) {
7435 entry->id = -1;
7436 memcpy(&entry->buf, FAULTED_STR, FAULTED_SIZE);
7437 written = -EFAULT;
7438 } else
7439 written = cnt;
7440
7441 __buffer_unlock_commit(buffer, event);
7442
7443 return written;
7444}
7445
7446static int tracing_clock_show(struct seq_file *m, void *v)
7447{
7448 struct trace_array *tr = m->private;
7449 int i;
7450
7451 for (i = 0; i < ARRAY_SIZE(trace_clocks); i++)
7452 seq_printf(m,
7453 "%s%s%s%s", i ? " " : "",
7454 i == tr->clock_id ? "[" : "", trace_clocks[i].name,
7455 i == tr->clock_id ? "]" : "");
7456 seq_putc(m, '\n');
7457
7458 return 0;
7459}
7460
7461int tracing_set_clock(struct trace_array *tr, const char *clockstr)
7462{
7463 int i;
7464
7465 for (i = 0; i < ARRAY_SIZE(trace_clocks); i++) {
7466 if (strcmp(trace_clocks[i].name, clockstr) == 0)
7467 break;
7468 }
7469 if (i == ARRAY_SIZE(trace_clocks))
7470 return -EINVAL;
7471
7472 mutex_lock(&trace_types_lock);
7473
7474 tr->clock_id = i;
7475
7476 ring_buffer_set_clock(tr->array_buffer.buffer, trace_clocks[i].func);
7477
7478 /*
7479 * New clock may not be consistent with the previous clock.
7480 * Reset the buffer so that it doesn't have incomparable timestamps.
7481 */
7482 tracing_reset_online_cpus(&tr->array_buffer);
7483
7484#ifdef CONFIG_TRACER_MAX_TRACE
7485 if (tr->max_buffer.buffer)
7486 ring_buffer_set_clock(tr->max_buffer.buffer, trace_clocks[i].func);
7487 tracing_reset_online_cpus(&tr->max_buffer);
7488#endif
7489
7490 mutex_unlock(&trace_types_lock);
7491
7492 return 0;
7493}
7494
7495static ssize_t tracing_clock_write(struct file *filp, const char __user *ubuf,
7496 size_t cnt, loff_t *fpos)
7497{
7498 struct seq_file *m = filp->private_data;
7499 struct trace_array *tr = m->private;
7500 char buf[64];
7501 const char *clockstr;
7502 int ret;
7503
7504 if (cnt >= sizeof(buf))
7505 return -EINVAL;
7506
7507 if (copy_from_user(buf, ubuf, cnt))
7508 return -EFAULT;
7509
7510 buf[cnt] = 0;
7511
7512 clockstr = strstrip(buf);
7513
7514 ret = tracing_set_clock(tr, clockstr);
7515 if (ret)
7516 return ret;
7517
7518 *fpos += cnt;
7519
7520 return cnt;
7521}
7522
7523static int tracing_clock_open(struct inode *inode, struct file *file)
7524{
7525 struct trace_array *tr = inode->i_private;
7526 int ret;
7527
7528 ret = tracing_check_open_get_tr(tr);
7529 if (ret)
7530 return ret;
7531
7532 ret = single_open(file, tracing_clock_show, inode->i_private);
7533 if (ret < 0)
7534 trace_array_put(tr);
7535
7536 return ret;
7537}
7538
7539static int tracing_time_stamp_mode_show(struct seq_file *m, void *v)
7540{
7541 struct trace_array *tr = m->private;
7542
7543 mutex_lock(&trace_types_lock);
7544
7545 if (ring_buffer_time_stamp_abs(tr->array_buffer.buffer))
7546 seq_puts(m, "delta [absolute]\n");
7547 else
7548 seq_puts(m, "[delta] absolute\n");
7549
7550 mutex_unlock(&trace_types_lock);
7551
7552 return 0;
7553}
7554
7555static int tracing_time_stamp_mode_open(struct inode *inode, struct file *file)
7556{
7557 struct trace_array *tr = inode->i_private;
7558 int ret;
7559
7560 ret = tracing_check_open_get_tr(tr);
7561 if (ret)
7562 return ret;
7563
7564 ret = single_open(file, tracing_time_stamp_mode_show, inode->i_private);
7565 if (ret < 0)
7566 trace_array_put(tr);
7567
7568 return ret;
7569}
7570
7571u64 tracing_event_time_stamp(struct trace_buffer *buffer, struct ring_buffer_event *rbe)
7572{
7573 if (rbe == this_cpu_read(trace_buffered_event))
7574 return ring_buffer_time_stamp(buffer);
7575
7576 return ring_buffer_event_time_stamp(buffer, rbe);
7577}
7578
7579/*
7580 * Set or disable using the per CPU trace_buffer_event when possible.
7581 */
7582int tracing_set_filter_buffering(struct trace_array *tr, bool set)
7583{
7584 int ret = 0;
7585
7586 mutex_lock(&trace_types_lock);
7587
7588 if (set && tr->no_filter_buffering_ref++)
7589 goto out;
7590
7591 if (!set) {
7592 if (WARN_ON_ONCE(!tr->no_filter_buffering_ref)) {
7593 ret = -EINVAL;
7594 goto out;
7595 }
7596
7597 --tr->no_filter_buffering_ref;
7598 }
7599 out:
7600 mutex_unlock(&trace_types_lock);
7601
7602 return ret;
7603}
7604
7605struct ftrace_buffer_info {
7606 struct trace_iterator iter;
7607 void *spare;
7608 unsigned int spare_cpu;
7609 unsigned int spare_size;
7610 unsigned int read;
7611};
7612
7613#ifdef CONFIG_TRACER_SNAPSHOT
7614static int tracing_snapshot_open(struct inode *inode, struct file *file)
7615{
7616 struct trace_array *tr = inode->i_private;
7617 struct trace_iterator *iter;
7618 struct seq_file *m;
7619 int ret;
7620
7621 ret = tracing_check_open_get_tr(tr);
7622 if (ret)
7623 return ret;
7624
7625 if (file->f_mode & FMODE_READ) {
7626 iter = __tracing_open(inode, file, true);
7627 if (IS_ERR(iter))
7628 ret = PTR_ERR(iter);
7629 } else {
7630 /* Writes still need the seq_file to hold the private data */
7631 ret = -ENOMEM;
7632 m = kzalloc(sizeof(*m), GFP_KERNEL);
7633 if (!m)
7634 goto out;
7635 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
7636 if (!iter) {
7637 kfree(m);
7638 goto out;
7639 }
7640 ret = 0;
7641
7642 iter->tr = tr;
7643 iter->array_buffer = &tr->max_buffer;
7644 iter->cpu_file = tracing_get_cpu(inode);
7645 m->private = iter;
7646 file->private_data = m;
7647 }
7648out:
7649 if (ret < 0)
7650 trace_array_put(tr);
7651
7652 return ret;
7653}
7654
7655static void tracing_swap_cpu_buffer(void *tr)
7656{
7657 update_max_tr_single((struct trace_array *)tr, current, smp_processor_id());
7658}
7659
7660static ssize_t
7661tracing_snapshot_write(struct file *filp, const char __user *ubuf, size_t cnt,
7662 loff_t *ppos)
7663{
7664 struct seq_file *m = filp->private_data;
7665 struct trace_iterator *iter = m->private;
7666 struct trace_array *tr = iter->tr;
7667 unsigned long val;
7668 int ret;
7669
7670 ret = tracing_update_buffers(tr);
7671 if (ret < 0)
7672 return ret;
7673
7674 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
7675 if (ret)
7676 return ret;
7677
7678 mutex_lock(&trace_types_lock);
7679
7680 if (tr->current_trace->use_max_tr) {
7681 ret = -EBUSY;
7682 goto out;
7683 }
7684
7685 local_irq_disable();
7686 arch_spin_lock(&tr->max_lock);
7687 if (tr->cond_snapshot)
7688 ret = -EBUSY;
7689 arch_spin_unlock(&tr->max_lock);
7690 local_irq_enable();
7691 if (ret)
7692 goto out;
7693
7694 switch (val) {
7695 case 0:
7696 if (iter->cpu_file != RING_BUFFER_ALL_CPUS) {
7697 ret = -EINVAL;
7698 break;
7699 }
7700 if (tr->allocated_snapshot)
7701 free_snapshot(tr);
7702 break;
7703 case 1:
7704/* Only allow per-cpu swap if the ring buffer supports it */
7705#ifndef CONFIG_RING_BUFFER_ALLOW_SWAP
7706 if (iter->cpu_file != RING_BUFFER_ALL_CPUS) {
7707 ret = -EINVAL;
7708 break;
7709 }
7710#endif
7711 if (tr->allocated_snapshot)
7712 ret = resize_buffer_duplicate_size(&tr->max_buffer,
7713 &tr->array_buffer, iter->cpu_file);
7714 else
7715 ret = tracing_alloc_snapshot_instance(tr);
7716 if (ret < 0)
7717 break;
7718 /* Now, we're going to swap */
7719 if (iter->cpu_file == RING_BUFFER_ALL_CPUS) {
7720 local_irq_disable();
7721 update_max_tr(tr, current, smp_processor_id(), NULL);
7722 local_irq_enable();
7723 } else {
7724 smp_call_function_single(iter->cpu_file, tracing_swap_cpu_buffer,
7725 (void *)tr, 1);
7726 }
7727 break;
7728 default:
7729 if (tr->allocated_snapshot) {
7730 if (iter->cpu_file == RING_BUFFER_ALL_CPUS)
7731 tracing_reset_online_cpus(&tr->max_buffer);
7732 else
7733 tracing_reset_cpu(&tr->max_buffer, iter->cpu_file);
7734 }
7735 break;
7736 }
7737
7738 if (ret >= 0) {
7739 *ppos += cnt;
7740 ret = cnt;
7741 }
7742out:
7743 mutex_unlock(&trace_types_lock);
7744 return ret;
7745}
7746
7747static int tracing_snapshot_release(struct inode *inode, struct file *file)
7748{
7749 struct seq_file *m = file->private_data;
7750 int ret;
7751
7752 ret = tracing_release(inode, file);
7753
7754 if (file->f_mode & FMODE_READ)
7755 return ret;
7756
7757 /* If write only, the seq_file is just a stub */
7758 if (m)
7759 kfree(m->private);
7760 kfree(m);
7761
7762 return 0;
7763}
7764
7765static int tracing_buffers_open(struct inode *inode, struct file *filp);
7766static ssize_t tracing_buffers_read(struct file *filp, char __user *ubuf,
7767 size_t count, loff_t *ppos);
7768static int tracing_buffers_release(struct inode *inode, struct file *file);
7769static ssize_t tracing_buffers_splice_read(struct file *file, loff_t *ppos,
7770 struct pipe_inode_info *pipe, size_t len, unsigned int flags);
7771
7772static int snapshot_raw_open(struct inode *inode, struct file *filp)
7773{
7774 struct ftrace_buffer_info *info;
7775 int ret;
7776
7777 /* The following checks for tracefs lockdown */
7778 ret = tracing_buffers_open(inode, filp);
7779 if (ret < 0)
7780 return ret;
7781
7782 info = filp->private_data;
7783
7784 if (info->iter.trace->use_max_tr) {
7785 tracing_buffers_release(inode, filp);
7786 return -EBUSY;
7787 }
7788
7789 info->iter.snapshot = true;
7790 info->iter.array_buffer = &info->iter.tr->max_buffer;
7791
7792 return ret;
7793}
7794
7795#endif /* CONFIG_TRACER_SNAPSHOT */
7796
7797
7798static const struct file_operations tracing_thresh_fops = {
7799 .open = tracing_open_generic,
7800 .read = tracing_thresh_read,
7801 .write = tracing_thresh_write,
7802 .llseek = generic_file_llseek,
7803};
7804
7805#ifdef CONFIG_TRACER_MAX_TRACE
7806static const struct file_operations tracing_max_lat_fops = {
7807 .open = tracing_open_generic_tr,
7808 .read = tracing_max_lat_read,
7809 .write = tracing_max_lat_write,
7810 .llseek = generic_file_llseek,
7811 .release = tracing_release_generic_tr,
7812};
7813#endif
7814
7815static const struct file_operations set_tracer_fops = {
7816 .open = tracing_open_generic_tr,
7817 .read = tracing_set_trace_read,
7818 .write = tracing_set_trace_write,
7819 .llseek = generic_file_llseek,
7820 .release = tracing_release_generic_tr,
7821};
7822
7823static const struct file_operations tracing_pipe_fops = {
7824 .open = tracing_open_pipe,
7825 .poll = tracing_poll_pipe,
7826 .read = tracing_read_pipe,
7827 .splice_read = tracing_splice_read_pipe,
7828 .release = tracing_release_pipe,
7829 .llseek = no_llseek,
7830};
7831
7832static const struct file_operations tracing_entries_fops = {
7833 .open = tracing_open_generic_tr,
7834 .read = tracing_entries_read,
7835 .write = tracing_entries_write,
7836 .llseek = generic_file_llseek,
7837 .release = tracing_release_generic_tr,
7838};
7839
7840static const struct file_operations tracing_total_entries_fops = {
7841 .open = tracing_open_generic_tr,
7842 .read = tracing_total_entries_read,
7843 .llseek = generic_file_llseek,
7844 .release = tracing_release_generic_tr,
7845};
7846
7847static const struct file_operations tracing_free_buffer_fops = {
7848 .open = tracing_open_generic_tr,
7849 .write = tracing_free_buffer_write,
7850 .release = tracing_free_buffer_release,
7851};
7852
7853static const struct file_operations tracing_mark_fops = {
7854 .open = tracing_mark_open,
7855 .write = tracing_mark_write,
7856 .release = tracing_release_generic_tr,
7857};
7858
7859static const struct file_operations tracing_mark_raw_fops = {
7860 .open = tracing_mark_open,
7861 .write = tracing_mark_raw_write,
7862 .release = tracing_release_generic_tr,
7863};
7864
7865static const struct file_operations trace_clock_fops = {
7866 .open = tracing_clock_open,
7867 .read = seq_read,
7868 .llseek = seq_lseek,
7869 .release = tracing_single_release_tr,
7870 .write = tracing_clock_write,
7871};
7872
7873static const struct file_operations trace_time_stamp_mode_fops = {
7874 .open = tracing_time_stamp_mode_open,
7875 .read = seq_read,
7876 .llseek = seq_lseek,
7877 .release = tracing_single_release_tr,
7878};
7879
7880#ifdef CONFIG_TRACER_SNAPSHOT
7881static const struct file_operations snapshot_fops = {
7882 .open = tracing_snapshot_open,
7883 .read = seq_read,
7884 .write = tracing_snapshot_write,
7885 .llseek = tracing_lseek,
7886 .release = tracing_snapshot_release,
7887};
7888
7889static const struct file_operations snapshot_raw_fops = {
7890 .open = snapshot_raw_open,
7891 .read = tracing_buffers_read,
7892 .release = tracing_buffers_release,
7893 .splice_read = tracing_buffers_splice_read,
7894 .llseek = no_llseek,
7895};
7896
7897#endif /* CONFIG_TRACER_SNAPSHOT */
7898
7899/*
7900 * trace_min_max_write - Write a u64 value to a trace_min_max_param struct
7901 * @filp: The active open file structure
7902 * @ubuf: The userspace provided buffer to read value into
7903 * @cnt: The maximum number of bytes to read
7904 * @ppos: The current "file" position
7905 *
7906 * This function implements the write interface for a struct trace_min_max_param.
7907 * The filp->private_data must point to a trace_min_max_param structure that
7908 * defines where to write the value, the min and the max acceptable values,
7909 * and a lock to protect the write.
7910 */
7911static ssize_t
7912trace_min_max_write(struct file *filp, const char __user *ubuf, size_t cnt, loff_t *ppos)
7913{
7914 struct trace_min_max_param *param = filp->private_data;
7915 u64 val;
7916 int err;
7917
7918 if (!param)
7919 return -EFAULT;
7920
7921 err = kstrtoull_from_user(ubuf, cnt, 10, &val);
7922 if (err)
7923 return err;
7924
7925 if (param->lock)
7926 mutex_lock(param->lock);
7927
7928 if (param->min && val < *param->min)
7929 err = -EINVAL;
7930
7931 if (param->max && val > *param->max)
7932 err = -EINVAL;
7933
7934 if (!err)
7935 *param->val = val;
7936
7937 if (param->lock)
7938 mutex_unlock(param->lock);
7939
7940 if (err)
7941 return err;
7942
7943 return cnt;
7944}
7945
7946/*
7947 * trace_min_max_read - Read a u64 value from a trace_min_max_param struct
7948 * @filp: The active open file structure
7949 * @ubuf: The userspace provided buffer to read value into
7950 * @cnt: The maximum number of bytes to read
7951 * @ppos: The current "file" position
7952 *
7953 * This function implements the read interface for a struct trace_min_max_param.
7954 * The filp->private_data must point to a trace_min_max_param struct with valid
7955 * data.
7956 */
7957static ssize_t
7958trace_min_max_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
7959{
7960 struct trace_min_max_param *param = filp->private_data;
7961 char buf[U64_STR_SIZE];
7962 int len;
7963 u64 val;
7964
7965 if (!param)
7966 return -EFAULT;
7967
7968 val = *param->val;
7969
7970 if (cnt > sizeof(buf))
7971 cnt = sizeof(buf);
7972
7973 len = snprintf(buf, sizeof(buf), "%llu\n", val);
7974
7975 return simple_read_from_buffer(ubuf, cnt, ppos, buf, len);
7976}
7977
7978const struct file_operations trace_min_max_fops = {
7979 .open = tracing_open_generic,
7980 .read = trace_min_max_read,
7981 .write = trace_min_max_write,
7982};
7983
7984#define TRACING_LOG_ERRS_MAX 8
7985#define TRACING_LOG_LOC_MAX 128
7986
7987#define CMD_PREFIX " Command: "
7988
7989struct err_info {
7990 const char **errs; /* ptr to loc-specific array of err strings */
7991 u8 type; /* index into errs -> specific err string */
7992 u16 pos; /* caret position */
7993 u64 ts;
7994};
7995
7996struct tracing_log_err {
7997 struct list_head list;
7998 struct err_info info;
7999 char loc[TRACING_LOG_LOC_MAX]; /* err location */
8000 char *cmd; /* what caused err */
8001};
8002
8003static DEFINE_MUTEX(tracing_err_log_lock);
8004
8005static struct tracing_log_err *alloc_tracing_log_err(int len)
8006{
8007 struct tracing_log_err *err;
8008
8009 err = kzalloc(sizeof(*err), GFP_KERNEL);
8010 if (!err)
8011 return ERR_PTR(-ENOMEM);
8012
8013 err->cmd = kzalloc(len, GFP_KERNEL);
8014 if (!err->cmd) {
8015 kfree(err);
8016 return ERR_PTR(-ENOMEM);
8017 }
8018
8019 return err;
8020}
8021
8022static void free_tracing_log_err(struct tracing_log_err *err)
8023{
8024 kfree(err->cmd);
8025 kfree(err);
8026}
8027
8028static struct tracing_log_err *get_tracing_log_err(struct trace_array *tr,
8029 int len)
8030{
8031 struct tracing_log_err *err;
8032 char *cmd;
8033
8034 if (tr->n_err_log_entries < TRACING_LOG_ERRS_MAX) {
8035 err = alloc_tracing_log_err(len);
8036 if (PTR_ERR(err) != -ENOMEM)
8037 tr->n_err_log_entries++;
8038
8039 return err;
8040 }
8041 cmd = kzalloc(len, GFP_KERNEL);
8042 if (!cmd)
8043 return ERR_PTR(-ENOMEM);
8044 err = list_first_entry(&tr->err_log, struct tracing_log_err, list);
8045 kfree(err->cmd);
8046 err->cmd = cmd;
8047 list_del(&err->list);
8048
8049 return err;
8050}
8051
8052/**
8053 * err_pos - find the position of a string within a command for error careting
8054 * @cmd: The tracing command that caused the error
8055 * @str: The string to position the caret at within @cmd
8056 *
8057 * Finds the position of the first occurrence of @str within @cmd. The
8058 * return value can be passed to tracing_log_err() for caret placement
8059 * within @cmd.
8060 *
8061 * Returns the index within @cmd of the first occurrence of @str or 0
8062 * if @str was not found.
8063 */
8064unsigned int err_pos(char *cmd, const char *str)
8065{
8066 char *found;
8067
8068 if (WARN_ON(!strlen(cmd)))
8069 return 0;
8070
8071 found = strstr(cmd, str);
8072 if (found)
8073 return found - cmd;
8074
8075 return 0;
8076}
8077
8078/**
8079 * tracing_log_err - write an error to the tracing error log
8080 * @tr: The associated trace array for the error (NULL for top level array)
8081 * @loc: A string describing where the error occurred
8082 * @cmd: The tracing command that caused the error
8083 * @errs: The array of loc-specific static error strings
8084 * @type: The index into errs[], which produces the specific static err string
8085 * @pos: The position the caret should be placed in the cmd
8086 *
8087 * Writes an error into tracing/error_log of the form:
8088 *
8089 * <loc>: error: <text>
8090 * Command: <cmd>
8091 * ^
8092 *
8093 * tracing/error_log is a small log file containing the last
8094 * TRACING_LOG_ERRS_MAX errors (8). Memory for errors isn't allocated
8095 * unless there has been a tracing error, and the error log can be
8096 * cleared and have its memory freed by writing the empty string in
8097 * truncation mode to it i.e. echo > tracing/error_log.
8098 *
8099 * NOTE: the @errs array along with the @type param are used to
8100 * produce a static error string - this string is not copied and saved
8101 * when the error is logged - only a pointer to it is saved. See
8102 * existing callers for examples of how static strings are typically
8103 * defined for use with tracing_log_err().
8104 */
8105void tracing_log_err(struct trace_array *tr,
8106 const char *loc, const char *cmd,
8107 const char **errs, u8 type, u16 pos)
8108{
8109 struct tracing_log_err *err;
8110 int len = 0;
8111
8112 if (!tr)
8113 tr = &global_trace;
8114
8115 len += sizeof(CMD_PREFIX) + 2 * sizeof("\n") + strlen(cmd) + 1;
8116
8117 mutex_lock(&tracing_err_log_lock);
8118 err = get_tracing_log_err(tr, len);
8119 if (PTR_ERR(err) == -ENOMEM) {
8120 mutex_unlock(&tracing_err_log_lock);
8121 return;
8122 }
8123
8124 snprintf(err->loc, TRACING_LOG_LOC_MAX, "%s: error: ", loc);
8125 snprintf(err->cmd, len, "\n" CMD_PREFIX "%s\n", cmd);
8126
8127 err->info.errs = errs;
8128 err->info.type = type;
8129 err->info.pos = pos;
8130 err->info.ts = local_clock();
8131
8132 list_add_tail(&err->list, &tr->err_log);
8133 mutex_unlock(&tracing_err_log_lock);
8134}
8135
8136static void clear_tracing_err_log(struct trace_array *tr)
8137{
8138 struct tracing_log_err *err, *next;
8139
8140 mutex_lock(&tracing_err_log_lock);
8141 list_for_each_entry_safe(err, next, &tr->err_log, list) {
8142 list_del(&err->list);
8143 free_tracing_log_err(err);
8144 }
8145
8146 tr->n_err_log_entries = 0;
8147 mutex_unlock(&tracing_err_log_lock);
8148}
8149
8150static void *tracing_err_log_seq_start(struct seq_file *m, loff_t *pos)
8151{
8152 struct trace_array *tr = m->private;
8153
8154 mutex_lock(&tracing_err_log_lock);
8155
8156 return seq_list_start(&tr->err_log, *pos);
8157}
8158
8159static void *tracing_err_log_seq_next(struct seq_file *m, void *v, loff_t *pos)
8160{
8161 struct trace_array *tr = m->private;
8162
8163 return seq_list_next(v, &tr->err_log, pos);
8164}
8165
8166static void tracing_err_log_seq_stop(struct seq_file *m, void *v)
8167{
8168 mutex_unlock(&tracing_err_log_lock);
8169}
8170
8171static void tracing_err_log_show_pos(struct seq_file *m, u16 pos)
8172{
8173 u16 i;
8174
8175 for (i = 0; i < sizeof(CMD_PREFIX) - 1; i++)
8176 seq_putc(m, ' ');
8177 for (i = 0; i < pos; i++)
8178 seq_putc(m, ' ');
8179 seq_puts(m, "^\n");
8180}
8181
8182static int tracing_err_log_seq_show(struct seq_file *m, void *v)
8183{
8184 struct tracing_log_err *err = v;
8185
8186 if (err) {
8187 const char *err_text = err->info.errs[err->info.type];
8188 u64 sec = err->info.ts;
8189 u32 nsec;
8190
8191 nsec = do_div(sec, NSEC_PER_SEC);
8192 seq_printf(m, "[%5llu.%06u] %s%s", sec, nsec / 1000,
8193 err->loc, err_text);
8194 seq_printf(m, "%s", err->cmd);
8195 tracing_err_log_show_pos(m, err->info.pos);
8196 }
8197
8198 return 0;
8199}
8200
8201static const struct seq_operations tracing_err_log_seq_ops = {
8202 .start = tracing_err_log_seq_start,
8203 .next = tracing_err_log_seq_next,
8204 .stop = tracing_err_log_seq_stop,
8205 .show = tracing_err_log_seq_show
8206};
8207
8208static int tracing_err_log_open(struct inode *inode, struct file *file)
8209{
8210 struct trace_array *tr = inode->i_private;
8211 int ret = 0;
8212
8213 ret = tracing_check_open_get_tr(tr);
8214 if (ret)
8215 return ret;
8216
8217 /* If this file was opened for write, then erase contents */
8218 if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC))
8219 clear_tracing_err_log(tr);
8220
8221 if (file->f_mode & FMODE_READ) {
8222 ret = seq_open(file, &tracing_err_log_seq_ops);
8223 if (!ret) {
8224 struct seq_file *m = file->private_data;
8225 m->private = tr;
8226 } else {
8227 trace_array_put(tr);
8228 }
8229 }
8230 return ret;
8231}
8232
8233static ssize_t tracing_err_log_write(struct file *file,
8234 const char __user *buffer,
8235 size_t count, loff_t *ppos)
8236{
8237 return count;
8238}
8239
8240static int tracing_err_log_release(struct inode *inode, struct file *file)
8241{
8242 struct trace_array *tr = inode->i_private;
8243
8244 trace_array_put(tr);
8245
8246 if (file->f_mode & FMODE_READ)
8247 seq_release(inode, file);
8248
8249 return 0;
8250}
8251
8252static const struct file_operations tracing_err_log_fops = {
8253 .open = tracing_err_log_open,
8254 .write = tracing_err_log_write,
8255 .read = seq_read,
8256 .llseek = tracing_lseek,
8257 .release = tracing_err_log_release,
8258};
8259
8260static int tracing_buffers_open(struct inode *inode, struct file *filp)
8261{
8262 struct trace_array *tr = inode->i_private;
8263 struct ftrace_buffer_info *info;
8264 int ret;
8265
8266 ret = tracing_check_open_get_tr(tr);
8267 if (ret)
8268 return ret;
8269
8270 info = kvzalloc(sizeof(*info), GFP_KERNEL);
8271 if (!info) {
8272 trace_array_put(tr);
8273 return -ENOMEM;
8274 }
8275
8276 mutex_lock(&trace_types_lock);
8277
8278 info->iter.tr = tr;
8279 info->iter.cpu_file = tracing_get_cpu(inode);
8280 info->iter.trace = tr->current_trace;
8281 info->iter.array_buffer = &tr->array_buffer;
8282 info->spare = NULL;
8283 /* Force reading ring buffer for first read */
8284 info->read = (unsigned int)-1;
8285
8286 filp->private_data = info;
8287
8288 tr->trace_ref++;
8289
8290 mutex_unlock(&trace_types_lock);
8291
8292 ret = nonseekable_open(inode, filp);
8293 if (ret < 0)
8294 trace_array_put(tr);
8295
8296 return ret;
8297}
8298
8299static __poll_t
8300tracing_buffers_poll(struct file *filp, poll_table *poll_table)
8301{
8302 struct ftrace_buffer_info *info = filp->private_data;
8303 struct trace_iterator *iter = &info->iter;
8304
8305 return trace_poll(iter, filp, poll_table);
8306}
8307
8308static ssize_t
8309tracing_buffers_read(struct file *filp, char __user *ubuf,
8310 size_t count, loff_t *ppos)
8311{
8312 struct ftrace_buffer_info *info = filp->private_data;
8313 struct trace_iterator *iter = &info->iter;
8314 void *trace_data;
8315 int page_size;
8316 ssize_t ret = 0;
8317 ssize_t size;
8318
8319 if (!count)
8320 return 0;
8321
8322#ifdef CONFIG_TRACER_MAX_TRACE
8323 if (iter->snapshot && iter->tr->current_trace->use_max_tr)
8324 return -EBUSY;
8325#endif
8326
8327 page_size = ring_buffer_subbuf_size_get(iter->array_buffer->buffer);
8328
8329 /* Make sure the spare matches the current sub buffer size */
8330 if (info->spare) {
8331 if (page_size != info->spare_size) {
8332 ring_buffer_free_read_page(iter->array_buffer->buffer,
8333 info->spare_cpu, info->spare);
8334 info->spare = NULL;
8335 }
8336 }
8337
8338 if (!info->spare) {
8339 info->spare = ring_buffer_alloc_read_page(iter->array_buffer->buffer,
8340 iter->cpu_file);
8341 if (IS_ERR(info->spare)) {
8342 ret = PTR_ERR(info->spare);
8343 info->spare = NULL;
8344 } else {
8345 info->spare_cpu = iter->cpu_file;
8346 info->spare_size = page_size;
8347 }
8348 }
8349 if (!info->spare)
8350 return ret;
8351
8352 /* Do we have previous read data to read? */
8353 if (info->read < page_size)
8354 goto read;
8355
8356 again:
8357 trace_access_lock(iter->cpu_file);
8358 ret = ring_buffer_read_page(iter->array_buffer->buffer,
8359 info->spare,
8360 count,
8361 iter->cpu_file, 0);
8362 trace_access_unlock(iter->cpu_file);
8363
8364 if (ret < 0) {
8365 if (trace_empty(iter)) {
8366 if ((filp->f_flags & O_NONBLOCK))
8367 return -EAGAIN;
8368
8369 ret = wait_on_pipe(iter, 0);
8370 if (ret)
8371 return ret;
8372
8373 goto again;
8374 }
8375 return 0;
8376 }
8377
8378 info->read = 0;
8379 read:
8380 size = page_size - info->read;
8381 if (size > count)
8382 size = count;
8383 trace_data = ring_buffer_read_page_data(info->spare);
8384 ret = copy_to_user(ubuf, trace_data + info->read, size);
8385 if (ret == size)
8386 return -EFAULT;
8387
8388 size -= ret;
8389
8390 *ppos += size;
8391 info->read += size;
8392
8393 return size;
8394}
8395
8396static int tracing_buffers_flush(struct file *file, fl_owner_t id)
8397{
8398 struct ftrace_buffer_info *info = file->private_data;
8399 struct trace_iterator *iter = &info->iter;
8400
8401 iter->wait_index++;
8402 /* Make sure the waiters see the new wait_index */
8403 smp_wmb();
8404
8405 ring_buffer_wake_waiters(iter->array_buffer->buffer, iter->cpu_file);
8406
8407 return 0;
8408}
8409
8410static int tracing_buffers_release(struct inode *inode, struct file *file)
8411{
8412 struct ftrace_buffer_info *info = file->private_data;
8413 struct trace_iterator *iter = &info->iter;
8414
8415 mutex_lock(&trace_types_lock);
8416
8417 iter->tr->trace_ref--;
8418
8419 __trace_array_put(iter->tr);
8420
8421 if (info->spare)
8422 ring_buffer_free_read_page(iter->array_buffer->buffer,
8423 info->spare_cpu, info->spare);
8424 kvfree(info);
8425
8426 mutex_unlock(&trace_types_lock);
8427
8428 return 0;
8429}
8430
8431struct buffer_ref {
8432 struct trace_buffer *buffer;
8433 void *page;
8434 int cpu;
8435 refcount_t refcount;
8436};
8437
8438static void buffer_ref_release(struct buffer_ref *ref)
8439{
8440 if (!refcount_dec_and_test(&ref->refcount))
8441 return;
8442 ring_buffer_free_read_page(ref->buffer, ref->cpu, ref->page);
8443 kfree(ref);
8444}
8445
8446static void buffer_pipe_buf_release(struct pipe_inode_info *pipe,
8447 struct pipe_buffer *buf)
8448{
8449 struct buffer_ref *ref = (struct buffer_ref *)buf->private;
8450
8451 buffer_ref_release(ref);
8452 buf->private = 0;
8453}
8454
8455static bool buffer_pipe_buf_get(struct pipe_inode_info *pipe,
8456 struct pipe_buffer *buf)
8457{
8458 struct buffer_ref *ref = (struct buffer_ref *)buf->private;
8459
8460 if (refcount_read(&ref->refcount) > INT_MAX/2)
8461 return false;
8462
8463 refcount_inc(&ref->refcount);
8464 return true;
8465}
8466
8467/* Pipe buffer operations for a buffer. */
8468static const struct pipe_buf_operations buffer_pipe_buf_ops = {
8469 .release = buffer_pipe_buf_release,
8470 .get = buffer_pipe_buf_get,
8471};
8472
8473/*
8474 * Callback from splice_to_pipe(), if we need to release some pages
8475 * at the end of the spd in case we error'ed out in filling the pipe.
8476 */
8477static void buffer_spd_release(struct splice_pipe_desc *spd, unsigned int i)
8478{
8479 struct buffer_ref *ref =
8480 (struct buffer_ref *)spd->partial[i].private;
8481
8482 buffer_ref_release(ref);
8483 spd->partial[i].private = 0;
8484}
8485
8486static ssize_t
8487tracing_buffers_splice_read(struct file *file, loff_t *ppos,
8488 struct pipe_inode_info *pipe, size_t len,
8489 unsigned int flags)
8490{
8491 struct ftrace_buffer_info *info = file->private_data;
8492 struct trace_iterator *iter = &info->iter;
8493 struct partial_page partial_def[PIPE_DEF_BUFFERS];
8494 struct page *pages_def[PIPE_DEF_BUFFERS];
8495 struct splice_pipe_desc spd = {
8496 .pages = pages_def,
8497 .partial = partial_def,
8498 .nr_pages_max = PIPE_DEF_BUFFERS,
8499 .ops = &buffer_pipe_buf_ops,
8500 .spd_release = buffer_spd_release,
8501 };
8502 struct buffer_ref *ref;
8503 int page_size;
8504 int entries, i;
8505 ssize_t ret = 0;
8506
8507#ifdef CONFIG_TRACER_MAX_TRACE
8508 if (iter->snapshot && iter->tr->current_trace->use_max_tr)
8509 return -EBUSY;
8510#endif
8511
8512 page_size = ring_buffer_subbuf_size_get(iter->array_buffer->buffer);
8513 if (*ppos & (page_size - 1))
8514 return -EINVAL;
8515
8516 if (len & (page_size - 1)) {
8517 if (len < page_size)
8518 return -EINVAL;
8519 len &= (~(page_size - 1));
8520 }
8521
8522 if (splice_grow_spd(pipe, &spd))
8523 return -ENOMEM;
8524
8525 again:
8526 trace_access_lock(iter->cpu_file);
8527 entries = ring_buffer_entries_cpu(iter->array_buffer->buffer, iter->cpu_file);
8528
8529 for (i = 0; i < spd.nr_pages_max && len && entries; i++, len -= page_size) {
8530 struct page *page;
8531 int r;
8532
8533 ref = kzalloc(sizeof(*ref), GFP_KERNEL);
8534 if (!ref) {
8535 ret = -ENOMEM;
8536 break;
8537 }
8538
8539 refcount_set(&ref->refcount, 1);
8540 ref->buffer = iter->array_buffer->buffer;
8541 ref->page = ring_buffer_alloc_read_page(ref->buffer, iter->cpu_file);
8542 if (IS_ERR(ref->page)) {
8543 ret = PTR_ERR(ref->page);
8544 ref->page = NULL;
8545 kfree(ref);
8546 break;
8547 }
8548 ref->cpu = iter->cpu_file;
8549
8550 r = ring_buffer_read_page(ref->buffer, ref->page,
8551 len, iter->cpu_file, 1);
8552 if (r < 0) {
8553 ring_buffer_free_read_page(ref->buffer, ref->cpu,
8554 ref->page);
8555 kfree(ref);
8556 break;
8557 }
8558
8559 page = virt_to_page(ring_buffer_read_page_data(ref->page));
8560
8561 spd.pages[i] = page;
8562 spd.partial[i].len = page_size;
8563 spd.partial[i].offset = 0;
8564 spd.partial[i].private = (unsigned long)ref;
8565 spd.nr_pages++;
8566 *ppos += page_size;
8567
8568 entries = ring_buffer_entries_cpu(iter->array_buffer->buffer, iter->cpu_file);
8569 }
8570
8571 trace_access_unlock(iter->cpu_file);
8572 spd.nr_pages = i;
8573
8574 /* did we read anything? */
8575 if (!spd.nr_pages) {
8576 long wait_index;
8577
8578 if (ret)
8579 goto out;
8580
8581 ret = -EAGAIN;
8582 if ((file->f_flags & O_NONBLOCK) || (flags & SPLICE_F_NONBLOCK))
8583 goto out;
8584
8585 wait_index = READ_ONCE(iter->wait_index);
8586
8587 ret = wait_on_pipe(iter, iter->snapshot ? 0 : iter->tr->buffer_percent);
8588 if (ret)
8589 goto out;
8590
8591 /* No need to wait after waking up when tracing is off */
8592 if (!tracer_tracing_is_on(iter->tr))
8593 goto out;
8594
8595 /* Make sure we see the new wait_index */
8596 smp_rmb();
8597 if (wait_index != iter->wait_index)
8598 goto out;
8599
8600 goto again;
8601 }
8602
8603 ret = splice_to_pipe(pipe, &spd);
8604out:
8605 splice_shrink_spd(&spd);
8606
8607 return ret;
8608}
8609
8610/* An ioctl call with cmd 0 to the ring buffer file will wake up all waiters */
8611static long tracing_buffers_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
8612{
8613 struct ftrace_buffer_info *info = file->private_data;
8614 struct trace_iterator *iter = &info->iter;
8615
8616 if (cmd)
8617 return -ENOIOCTLCMD;
8618
8619 mutex_lock(&trace_types_lock);
8620
8621 iter->wait_index++;
8622 /* Make sure the waiters see the new wait_index */
8623 smp_wmb();
8624
8625 ring_buffer_wake_waiters(iter->array_buffer->buffer, iter->cpu_file);
8626
8627 mutex_unlock(&trace_types_lock);
8628 return 0;
8629}
8630
8631static const struct file_operations tracing_buffers_fops = {
8632 .open = tracing_buffers_open,
8633 .read = tracing_buffers_read,
8634 .poll = tracing_buffers_poll,
8635 .release = tracing_buffers_release,
8636 .flush = tracing_buffers_flush,
8637 .splice_read = tracing_buffers_splice_read,
8638 .unlocked_ioctl = tracing_buffers_ioctl,
8639 .llseek = no_llseek,
8640};
8641
8642static ssize_t
8643tracing_stats_read(struct file *filp, char __user *ubuf,
8644 size_t count, loff_t *ppos)
8645{
8646 struct inode *inode = file_inode(filp);
8647 struct trace_array *tr = inode->i_private;
8648 struct array_buffer *trace_buf = &tr->array_buffer;
8649 int cpu = tracing_get_cpu(inode);
8650 struct trace_seq *s;
8651 unsigned long cnt;
8652 unsigned long long t;
8653 unsigned long usec_rem;
8654
8655 s = kmalloc(sizeof(*s), GFP_KERNEL);
8656 if (!s)
8657 return -ENOMEM;
8658
8659 trace_seq_init(s);
8660
8661 cnt = ring_buffer_entries_cpu(trace_buf->buffer, cpu);
8662 trace_seq_printf(s, "entries: %ld\n", cnt);
8663
8664 cnt = ring_buffer_overrun_cpu(trace_buf->buffer, cpu);
8665 trace_seq_printf(s, "overrun: %ld\n", cnt);
8666
8667 cnt = ring_buffer_commit_overrun_cpu(trace_buf->buffer, cpu);
8668 trace_seq_printf(s, "commit overrun: %ld\n", cnt);
8669
8670 cnt = ring_buffer_bytes_cpu(trace_buf->buffer, cpu);
8671 trace_seq_printf(s, "bytes: %ld\n", cnt);
8672
8673 if (trace_clocks[tr->clock_id].in_ns) {
8674 /* local or global for trace_clock */
8675 t = ns2usecs(ring_buffer_oldest_event_ts(trace_buf->buffer, cpu));
8676 usec_rem = do_div(t, USEC_PER_SEC);
8677 trace_seq_printf(s, "oldest event ts: %5llu.%06lu\n",
8678 t, usec_rem);
8679
8680 t = ns2usecs(ring_buffer_time_stamp(trace_buf->buffer));
8681 usec_rem = do_div(t, USEC_PER_SEC);
8682 trace_seq_printf(s, "now ts: %5llu.%06lu\n", t, usec_rem);
8683 } else {
8684 /* counter or tsc mode for trace_clock */
8685 trace_seq_printf(s, "oldest event ts: %llu\n",
8686 ring_buffer_oldest_event_ts(trace_buf->buffer, cpu));
8687
8688 trace_seq_printf(s, "now ts: %llu\n",
8689 ring_buffer_time_stamp(trace_buf->buffer));
8690 }
8691
8692 cnt = ring_buffer_dropped_events_cpu(trace_buf->buffer, cpu);
8693 trace_seq_printf(s, "dropped events: %ld\n", cnt);
8694
8695 cnt = ring_buffer_read_events_cpu(trace_buf->buffer, cpu);
8696 trace_seq_printf(s, "read events: %ld\n", cnt);
8697
8698 count = simple_read_from_buffer(ubuf, count, ppos,
8699 s->buffer, trace_seq_used(s));
8700
8701 kfree(s);
8702
8703 return count;
8704}
8705
8706static const struct file_operations tracing_stats_fops = {
8707 .open = tracing_open_generic_tr,
8708 .read = tracing_stats_read,
8709 .llseek = generic_file_llseek,
8710 .release = tracing_release_generic_tr,
8711};
8712
8713#ifdef CONFIG_DYNAMIC_FTRACE
8714
8715static ssize_t
8716tracing_read_dyn_info(struct file *filp, char __user *ubuf,
8717 size_t cnt, loff_t *ppos)
8718{
8719 ssize_t ret;
8720 char *buf;
8721 int r;
8722
8723 /* 256 should be plenty to hold the amount needed */
8724 buf = kmalloc(256, GFP_KERNEL);
8725 if (!buf)
8726 return -ENOMEM;
8727
8728 r = scnprintf(buf, 256, "%ld pages:%ld groups: %ld\n",
8729 ftrace_update_tot_cnt,
8730 ftrace_number_of_pages,
8731 ftrace_number_of_groups);
8732
8733 ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
8734 kfree(buf);
8735 return ret;
8736}
8737
8738static const struct file_operations tracing_dyn_info_fops = {
8739 .open = tracing_open_generic,
8740 .read = tracing_read_dyn_info,
8741 .llseek = generic_file_llseek,
8742};
8743#endif /* CONFIG_DYNAMIC_FTRACE */
8744
8745#if defined(CONFIG_TRACER_SNAPSHOT) && defined(CONFIG_DYNAMIC_FTRACE)
8746static void
8747ftrace_snapshot(unsigned long ip, unsigned long parent_ip,
8748 struct trace_array *tr, struct ftrace_probe_ops *ops,
8749 void *data)
8750{
8751 tracing_snapshot_instance(tr);
8752}
8753
8754static void
8755ftrace_count_snapshot(unsigned long ip, unsigned long parent_ip,
8756 struct trace_array *tr, struct ftrace_probe_ops *ops,
8757 void *data)
8758{
8759 struct ftrace_func_mapper *mapper = data;
8760 long *count = NULL;
8761
8762 if (mapper)
8763 count = (long *)ftrace_func_mapper_find_ip(mapper, ip);
8764
8765 if (count) {
8766
8767 if (*count <= 0)
8768 return;
8769
8770 (*count)--;
8771 }
8772
8773 tracing_snapshot_instance(tr);
8774}
8775
8776static int
8777ftrace_snapshot_print(struct seq_file *m, unsigned long ip,
8778 struct ftrace_probe_ops *ops, void *data)
8779{
8780 struct ftrace_func_mapper *mapper = data;
8781 long *count = NULL;
8782
8783 seq_printf(m, "%ps:", (void *)ip);
8784
8785 seq_puts(m, "snapshot");
8786
8787 if (mapper)
8788 count = (long *)ftrace_func_mapper_find_ip(mapper, ip);
8789
8790 if (count)
8791 seq_printf(m, ":count=%ld\n", *count);
8792 else
8793 seq_puts(m, ":unlimited\n");
8794
8795 return 0;
8796}
8797
8798static int
8799ftrace_snapshot_init(struct ftrace_probe_ops *ops, struct trace_array *tr,
8800 unsigned long ip, void *init_data, void **data)
8801{
8802 struct ftrace_func_mapper *mapper = *data;
8803
8804 if (!mapper) {
8805 mapper = allocate_ftrace_func_mapper();
8806 if (!mapper)
8807 return -ENOMEM;
8808 *data = mapper;
8809 }
8810
8811 return ftrace_func_mapper_add_ip(mapper, ip, init_data);
8812}
8813
8814static void
8815ftrace_snapshot_free(struct ftrace_probe_ops *ops, struct trace_array *tr,
8816 unsigned long ip, void *data)
8817{
8818 struct ftrace_func_mapper *mapper = data;
8819
8820 if (!ip) {
8821 if (!mapper)
8822 return;
8823 free_ftrace_func_mapper(mapper, NULL);
8824 return;
8825 }
8826
8827 ftrace_func_mapper_remove_ip(mapper, ip);
8828}
8829
8830static struct ftrace_probe_ops snapshot_probe_ops = {
8831 .func = ftrace_snapshot,
8832 .print = ftrace_snapshot_print,
8833};
8834
8835static struct ftrace_probe_ops snapshot_count_probe_ops = {
8836 .func = ftrace_count_snapshot,
8837 .print = ftrace_snapshot_print,
8838 .init = ftrace_snapshot_init,
8839 .free = ftrace_snapshot_free,
8840};
8841
8842static int
8843ftrace_trace_snapshot_callback(struct trace_array *tr, struct ftrace_hash *hash,
8844 char *glob, char *cmd, char *param, int enable)
8845{
8846 struct ftrace_probe_ops *ops;
8847 void *count = (void *)-1;
8848 char *number;
8849 int ret;
8850
8851 if (!tr)
8852 return -ENODEV;
8853
8854 /* hash funcs only work with set_ftrace_filter */
8855 if (!enable)
8856 return -EINVAL;
8857
8858 ops = param ? &snapshot_count_probe_ops : &snapshot_probe_ops;
8859
8860 if (glob[0] == '!')
8861 return unregister_ftrace_function_probe_func(glob+1, tr, ops);
8862
8863 if (!param)
8864 goto out_reg;
8865
8866 number = strsep(¶m, ":");
8867
8868 if (!strlen(number))
8869 goto out_reg;
8870
8871 /*
8872 * We use the callback data field (which is a pointer)
8873 * as our counter.
8874 */
8875 ret = kstrtoul(number, 0, (unsigned long *)&count);
8876 if (ret)
8877 return ret;
8878
8879 out_reg:
8880 ret = tracing_alloc_snapshot_instance(tr);
8881 if (ret < 0)
8882 goto out;
8883
8884 ret = register_ftrace_function_probe(glob, tr, ops, count);
8885
8886 out:
8887 return ret < 0 ? ret : 0;
8888}
8889
8890static struct ftrace_func_command ftrace_snapshot_cmd = {
8891 .name = "snapshot",
8892 .func = ftrace_trace_snapshot_callback,
8893};
8894
8895static __init int register_snapshot_cmd(void)
8896{
8897 return register_ftrace_command(&ftrace_snapshot_cmd);
8898}
8899#else
8900static inline __init int register_snapshot_cmd(void) { return 0; }
8901#endif /* defined(CONFIG_TRACER_SNAPSHOT) && defined(CONFIG_DYNAMIC_FTRACE) */
8902
8903static struct dentry *tracing_get_dentry(struct trace_array *tr)
8904{
8905 if (WARN_ON(!tr->dir))
8906 return ERR_PTR(-ENODEV);
8907
8908 /* Top directory uses NULL as the parent */
8909 if (tr->flags & TRACE_ARRAY_FL_GLOBAL)
8910 return NULL;
8911
8912 /* All sub buffers have a descriptor */
8913 return tr->dir;
8914}
8915
8916static struct dentry *tracing_dentry_percpu(struct trace_array *tr, int cpu)
8917{
8918 struct dentry *d_tracer;
8919
8920 if (tr->percpu_dir)
8921 return tr->percpu_dir;
8922
8923 d_tracer = tracing_get_dentry(tr);
8924 if (IS_ERR(d_tracer))
8925 return NULL;
8926
8927 tr->percpu_dir = tracefs_create_dir("per_cpu", d_tracer);
8928
8929 MEM_FAIL(!tr->percpu_dir,
8930 "Could not create tracefs directory 'per_cpu/%d'\n", cpu);
8931
8932 return tr->percpu_dir;
8933}
8934
8935static struct dentry *
8936trace_create_cpu_file(const char *name, umode_t mode, struct dentry *parent,
8937 void *data, long cpu, const struct file_operations *fops)
8938{
8939 struct dentry *ret = trace_create_file(name, mode, parent, data, fops);
8940
8941 if (ret) /* See tracing_get_cpu() */
8942 d_inode(ret)->i_cdev = (void *)(cpu + 1);
8943 return ret;
8944}
8945
8946static void
8947tracing_init_tracefs_percpu(struct trace_array *tr, long cpu)
8948{
8949 struct dentry *d_percpu = tracing_dentry_percpu(tr, cpu);
8950 struct dentry *d_cpu;
8951 char cpu_dir[30]; /* 30 characters should be more than enough */
8952
8953 if (!d_percpu)
8954 return;
8955
8956 snprintf(cpu_dir, 30, "cpu%ld", cpu);
8957 d_cpu = tracefs_create_dir(cpu_dir, d_percpu);
8958 if (!d_cpu) {
8959 pr_warn("Could not create tracefs '%s' entry\n", cpu_dir);
8960 return;
8961 }
8962
8963 /* per cpu trace_pipe */
8964 trace_create_cpu_file("trace_pipe", TRACE_MODE_READ, d_cpu,
8965 tr, cpu, &tracing_pipe_fops);
8966
8967 /* per cpu trace */
8968 trace_create_cpu_file("trace", TRACE_MODE_WRITE, d_cpu,
8969 tr, cpu, &tracing_fops);
8970
8971 trace_create_cpu_file("trace_pipe_raw", TRACE_MODE_READ, d_cpu,
8972 tr, cpu, &tracing_buffers_fops);
8973
8974 trace_create_cpu_file("stats", TRACE_MODE_READ, d_cpu,
8975 tr, cpu, &tracing_stats_fops);
8976
8977 trace_create_cpu_file("buffer_size_kb", TRACE_MODE_READ, d_cpu,
8978 tr, cpu, &tracing_entries_fops);
8979
8980#ifdef CONFIG_TRACER_SNAPSHOT
8981 trace_create_cpu_file("snapshot", TRACE_MODE_WRITE, d_cpu,
8982 tr, cpu, &snapshot_fops);
8983
8984 trace_create_cpu_file("snapshot_raw", TRACE_MODE_READ, d_cpu,
8985 tr, cpu, &snapshot_raw_fops);
8986#endif
8987}
8988
8989#ifdef CONFIG_FTRACE_SELFTEST
8990/* Let selftest have access to static functions in this file */
8991#include "trace_selftest.c"
8992#endif
8993
8994static ssize_t
8995trace_options_read(struct file *filp, char __user *ubuf, size_t cnt,
8996 loff_t *ppos)
8997{
8998 struct trace_option_dentry *topt = filp->private_data;
8999 char *buf;
9000
9001 if (topt->flags->val & topt->opt->bit)
9002 buf = "1\n";
9003 else
9004 buf = "0\n";
9005
9006 return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
9007}
9008
9009static ssize_t
9010trace_options_write(struct file *filp, const char __user *ubuf, size_t cnt,
9011 loff_t *ppos)
9012{
9013 struct trace_option_dentry *topt = filp->private_data;
9014 unsigned long val;
9015 int ret;
9016
9017 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
9018 if (ret)
9019 return ret;
9020
9021 if (val != 0 && val != 1)
9022 return -EINVAL;
9023
9024 if (!!(topt->flags->val & topt->opt->bit) != val) {
9025 mutex_lock(&trace_types_lock);
9026 ret = __set_tracer_option(topt->tr, topt->flags,
9027 topt->opt, !val);
9028 mutex_unlock(&trace_types_lock);
9029 if (ret)
9030 return ret;
9031 }
9032
9033 *ppos += cnt;
9034
9035 return cnt;
9036}
9037
9038static int tracing_open_options(struct inode *inode, struct file *filp)
9039{
9040 struct trace_option_dentry *topt = inode->i_private;
9041 int ret;
9042
9043 ret = tracing_check_open_get_tr(topt->tr);
9044 if (ret)
9045 return ret;
9046
9047 filp->private_data = inode->i_private;
9048 return 0;
9049}
9050
9051static int tracing_release_options(struct inode *inode, struct file *file)
9052{
9053 struct trace_option_dentry *topt = file->private_data;
9054
9055 trace_array_put(topt->tr);
9056 return 0;
9057}
9058
9059static const struct file_operations trace_options_fops = {
9060 .open = tracing_open_options,
9061 .read = trace_options_read,
9062 .write = trace_options_write,
9063 .llseek = generic_file_llseek,
9064 .release = tracing_release_options,
9065};
9066
9067/*
9068 * In order to pass in both the trace_array descriptor as well as the index
9069 * to the flag that the trace option file represents, the trace_array
9070 * has a character array of trace_flags_index[], which holds the index
9071 * of the bit for the flag it represents. index[0] == 0, index[1] == 1, etc.
9072 * The address of this character array is passed to the flag option file
9073 * read/write callbacks.
9074 *
9075 * In order to extract both the index and the trace_array descriptor,
9076 * get_tr_index() uses the following algorithm.
9077 *
9078 * idx = *ptr;
9079 *
9080 * As the pointer itself contains the address of the index (remember
9081 * index[1] == 1).
9082 *
9083 * Then to get the trace_array descriptor, by subtracting that index
9084 * from the ptr, we get to the start of the index itself.
9085 *
9086 * ptr - idx == &index[0]
9087 *
9088 * Then a simple container_of() from that pointer gets us to the
9089 * trace_array descriptor.
9090 */
9091static void get_tr_index(void *data, struct trace_array **ptr,
9092 unsigned int *pindex)
9093{
9094 *pindex = *(unsigned char *)data;
9095
9096 *ptr = container_of(data - *pindex, struct trace_array,
9097 trace_flags_index);
9098}
9099
9100static ssize_t
9101trace_options_core_read(struct file *filp, char __user *ubuf, size_t cnt,
9102 loff_t *ppos)
9103{
9104 void *tr_index = filp->private_data;
9105 struct trace_array *tr;
9106 unsigned int index;
9107 char *buf;
9108
9109 get_tr_index(tr_index, &tr, &index);
9110
9111 if (tr->trace_flags & (1 << index))
9112 buf = "1\n";
9113 else
9114 buf = "0\n";
9115
9116 return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
9117}
9118
9119static ssize_t
9120trace_options_core_write(struct file *filp, const char __user *ubuf, size_t cnt,
9121 loff_t *ppos)
9122{
9123 void *tr_index = filp->private_data;
9124 struct trace_array *tr;
9125 unsigned int index;
9126 unsigned long val;
9127 int ret;
9128
9129 get_tr_index(tr_index, &tr, &index);
9130
9131 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
9132 if (ret)
9133 return ret;
9134
9135 if (val != 0 && val != 1)
9136 return -EINVAL;
9137
9138 mutex_lock(&event_mutex);
9139 mutex_lock(&trace_types_lock);
9140 ret = set_tracer_flag(tr, 1 << index, val);
9141 mutex_unlock(&trace_types_lock);
9142 mutex_unlock(&event_mutex);
9143
9144 if (ret < 0)
9145 return ret;
9146
9147 *ppos += cnt;
9148
9149 return cnt;
9150}
9151
9152static const struct file_operations trace_options_core_fops = {
9153 .open = tracing_open_generic,
9154 .read = trace_options_core_read,
9155 .write = trace_options_core_write,
9156 .llseek = generic_file_llseek,
9157};
9158
9159struct dentry *trace_create_file(const char *name,
9160 umode_t mode,
9161 struct dentry *parent,
9162 void *data,
9163 const struct file_operations *fops)
9164{
9165 struct dentry *ret;
9166
9167 ret = tracefs_create_file(name, mode, parent, data, fops);
9168 if (!ret)
9169 pr_warn("Could not create tracefs '%s' entry\n", name);
9170
9171 return ret;
9172}
9173
9174
9175static struct dentry *trace_options_init_dentry(struct trace_array *tr)
9176{
9177 struct dentry *d_tracer;
9178
9179 if (tr->options)
9180 return tr->options;
9181
9182 d_tracer = tracing_get_dentry(tr);
9183 if (IS_ERR(d_tracer))
9184 return NULL;
9185
9186 tr->options = tracefs_create_dir("options", d_tracer);
9187 if (!tr->options) {
9188 pr_warn("Could not create tracefs directory 'options'\n");
9189 return NULL;
9190 }
9191
9192 return tr->options;
9193}
9194
9195static void
9196create_trace_option_file(struct trace_array *tr,
9197 struct trace_option_dentry *topt,
9198 struct tracer_flags *flags,
9199 struct tracer_opt *opt)
9200{
9201 struct dentry *t_options;
9202
9203 t_options = trace_options_init_dentry(tr);
9204 if (!t_options)
9205 return;
9206
9207 topt->flags = flags;
9208 topt->opt = opt;
9209 topt->tr = tr;
9210
9211 topt->entry = trace_create_file(opt->name, TRACE_MODE_WRITE,
9212 t_options, topt, &trace_options_fops);
9213
9214}
9215
9216static void
9217create_trace_option_files(struct trace_array *tr, struct tracer *tracer)
9218{
9219 struct trace_option_dentry *topts;
9220 struct trace_options *tr_topts;
9221 struct tracer_flags *flags;
9222 struct tracer_opt *opts;
9223 int cnt;
9224 int i;
9225
9226 if (!tracer)
9227 return;
9228
9229 flags = tracer->flags;
9230
9231 if (!flags || !flags->opts)
9232 return;
9233
9234 /*
9235 * If this is an instance, only create flags for tracers
9236 * the instance may have.
9237 */
9238 if (!trace_ok_for_array(tracer, tr))
9239 return;
9240
9241 for (i = 0; i < tr->nr_topts; i++) {
9242 /* Make sure there's no duplicate flags. */
9243 if (WARN_ON_ONCE(tr->topts[i].tracer->flags == tracer->flags))
9244 return;
9245 }
9246
9247 opts = flags->opts;
9248
9249 for (cnt = 0; opts[cnt].name; cnt++)
9250 ;
9251
9252 topts = kcalloc(cnt + 1, sizeof(*topts), GFP_KERNEL);
9253 if (!topts)
9254 return;
9255
9256 tr_topts = krealloc(tr->topts, sizeof(*tr->topts) * (tr->nr_topts + 1),
9257 GFP_KERNEL);
9258 if (!tr_topts) {
9259 kfree(topts);
9260 return;
9261 }
9262
9263 tr->topts = tr_topts;
9264 tr->topts[tr->nr_topts].tracer = tracer;
9265 tr->topts[tr->nr_topts].topts = topts;
9266 tr->nr_topts++;
9267
9268 for (cnt = 0; opts[cnt].name; cnt++) {
9269 create_trace_option_file(tr, &topts[cnt], flags,
9270 &opts[cnt]);
9271 MEM_FAIL(topts[cnt].entry == NULL,
9272 "Failed to create trace option: %s",
9273 opts[cnt].name);
9274 }
9275}
9276
9277static struct dentry *
9278create_trace_option_core_file(struct trace_array *tr,
9279 const char *option, long index)
9280{
9281 struct dentry *t_options;
9282
9283 t_options = trace_options_init_dentry(tr);
9284 if (!t_options)
9285 return NULL;
9286
9287 return trace_create_file(option, TRACE_MODE_WRITE, t_options,
9288 (void *)&tr->trace_flags_index[index],
9289 &trace_options_core_fops);
9290}
9291
9292static void create_trace_options_dir(struct trace_array *tr)
9293{
9294 struct dentry *t_options;
9295 bool top_level = tr == &global_trace;
9296 int i;
9297
9298 t_options = trace_options_init_dentry(tr);
9299 if (!t_options)
9300 return;
9301
9302 for (i = 0; trace_options[i]; i++) {
9303 if (top_level ||
9304 !((1 << i) & TOP_LEVEL_TRACE_FLAGS))
9305 create_trace_option_core_file(tr, trace_options[i], i);
9306 }
9307}
9308
9309static ssize_t
9310rb_simple_read(struct file *filp, char __user *ubuf,
9311 size_t cnt, loff_t *ppos)
9312{
9313 struct trace_array *tr = filp->private_data;
9314 char buf[64];
9315 int r;
9316
9317 r = tracer_tracing_is_on(tr);
9318 r = sprintf(buf, "%d\n", r);
9319
9320 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
9321}
9322
9323static ssize_t
9324rb_simple_write(struct file *filp, const char __user *ubuf,
9325 size_t cnt, loff_t *ppos)
9326{
9327 struct trace_array *tr = filp->private_data;
9328 struct trace_buffer *buffer = tr->array_buffer.buffer;
9329 unsigned long val;
9330 int ret;
9331
9332 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
9333 if (ret)
9334 return ret;
9335
9336 if (buffer) {
9337 mutex_lock(&trace_types_lock);
9338 if (!!val == tracer_tracing_is_on(tr)) {
9339 val = 0; /* do nothing */
9340 } else if (val) {
9341 tracer_tracing_on(tr);
9342 if (tr->current_trace->start)
9343 tr->current_trace->start(tr);
9344 } else {
9345 tracer_tracing_off(tr);
9346 if (tr->current_trace->stop)
9347 tr->current_trace->stop(tr);
9348 /* Wake up any waiters */
9349 ring_buffer_wake_waiters(buffer, RING_BUFFER_ALL_CPUS);
9350 }
9351 mutex_unlock(&trace_types_lock);
9352 }
9353
9354 (*ppos)++;
9355
9356 return cnt;
9357}
9358
9359static const struct file_operations rb_simple_fops = {
9360 .open = tracing_open_generic_tr,
9361 .read = rb_simple_read,
9362 .write = rb_simple_write,
9363 .release = tracing_release_generic_tr,
9364 .llseek = default_llseek,
9365};
9366
9367static ssize_t
9368buffer_percent_read(struct file *filp, char __user *ubuf,
9369 size_t cnt, loff_t *ppos)
9370{
9371 struct trace_array *tr = filp->private_data;
9372 char buf[64];
9373 int r;
9374
9375 r = tr->buffer_percent;
9376 r = sprintf(buf, "%d\n", r);
9377
9378 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
9379}
9380
9381static ssize_t
9382buffer_percent_write(struct file *filp, const char __user *ubuf,
9383 size_t cnt, loff_t *ppos)
9384{
9385 struct trace_array *tr = filp->private_data;
9386 unsigned long val;
9387 int ret;
9388
9389 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
9390 if (ret)
9391 return ret;
9392
9393 if (val > 100)
9394 return -EINVAL;
9395
9396 tr->buffer_percent = val;
9397
9398 (*ppos)++;
9399
9400 return cnt;
9401}
9402
9403static const struct file_operations buffer_percent_fops = {
9404 .open = tracing_open_generic_tr,
9405 .read = buffer_percent_read,
9406 .write = buffer_percent_write,
9407 .release = tracing_release_generic_tr,
9408 .llseek = default_llseek,
9409};
9410
9411static ssize_t
9412buffer_subbuf_size_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos)
9413{
9414 struct trace_array *tr = filp->private_data;
9415 size_t size;
9416 char buf[64];
9417 int order;
9418 int r;
9419
9420 order = ring_buffer_subbuf_order_get(tr->array_buffer.buffer);
9421 size = (PAGE_SIZE << order) / 1024;
9422
9423 r = sprintf(buf, "%zd\n", size);
9424
9425 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
9426}
9427
9428static ssize_t
9429buffer_subbuf_size_write(struct file *filp, const char __user *ubuf,
9430 size_t cnt, loff_t *ppos)
9431{
9432 struct trace_array *tr = filp->private_data;
9433 unsigned long val;
9434 int old_order;
9435 int order;
9436 int pages;
9437 int ret;
9438
9439 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
9440 if (ret)
9441 return ret;
9442
9443 val *= 1024; /* value passed in is in KB */
9444
9445 pages = DIV_ROUND_UP(val, PAGE_SIZE);
9446 order = fls(pages - 1);
9447
9448 /* limit between 1 and 128 system pages */
9449 if (order < 0 || order > 7)
9450 return -EINVAL;
9451
9452 /* Do not allow tracing while changing the order of the ring buffer */
9453 tracing_stop_tr(tr);
9454
9455 old_order = ring_buffer_subbuf_order_get(tr->array_buffer.buffer);
9456 if (old_order == order)
9457 goto out;
9458
9459 ret = ring_buffer_subbuf_order_set(tr->array_buffer.buffer, order);
9460 if (ret)
9461 goto out;
9462
9463#ifdef CONFIG_TRACER_MAX_TRACE
9464
9465 if (!tr->allocated_snapshot)
9466 goto out_max;
9467
9468 ret = ring_buffer_subbuf_order_set(tr->max_buffer.buffer, order);
9469 if (ret) {
9470 /* Put back the old order */
9471 cnt = ring_buffer_subbuf_order_set(tr->array_buffer.buffer, old_order);
9472 if (WARN_ON_ONCE(cnt)) {
9473 /*
9474 * AARGH! We are left with different orders!
9475 * The max buffer is our "snapshot" buffer.
9476 * When a tracer needs a snapshot (one of the
9477 * latency tracers), it swaps the max buffer
9478 * with the saved snap shot. We succeeded to
9479 * update the order of the main buffer, but failed to
9480 * update the order of the max buffer. But when we tried
9481 * to reset the main buffer to the original size, we
9482 * failed there too. This is very unlikely to
9483 * happen, but if it does, warn and kill all
9484 * tracing.
9485 */
9486 tracing_disabled = 1;
9487 }
9488 goto out;
9489 }
9490 out_max:
9491#endif
9492 (*ppos)++;
9493 out:
9494 if (ret)
9495 cnt = ret;
9496 tracing_start_tr(tr);
9497 return cnt;
9498}
9499
9500static const struct file_operations buffer_subbuf_size_fops = {
9501 .open = tracing_open_generic_tr,
9502 .read = buffer_subbuf_size_read,
9503 .write = buffer_subbuf_size_write,
9504 .release = tracing_release_generic_tr,
9505 .llseek = default_llseek,
9506};
9507
9508static struct dentry *trace_instance_dir;
9509
9510static void
9511init_tracer_tracefs(struct trace_array *tr, struct dentry *d_tracer);
9512
9513static int
9514allocate_trace_buffer(struct trace_array *tr, struct array_buffer *buf, int size)
9515{
9516 enum ring_buffer_flags rb_flags;
9517
9518 rb_flags = tr->trace_flags & TRACE_ITER_OVERWRITE ? RB_FL_OVERWRITE : 0;
9519
9520 buf->tr = tr;
9521
9522 buf->buffer = ring_buffer_alloc(size, rb_flags);
9523 if (!buf->buffer)
9524 return -ENOMEM;
9525
9526 buf->data = alloc_percpu(struct trace_array_cpu);
9527 if (!buf->data) {
9528 ring_buffer_free(buf->buffer);
9529 buf->buffer = NULL;
9530 return -ENOMEM;
9531 }
9532
9533 /* Allocate the first page for all buffers */
9534 set_buffer_entries(&tr->array_buffer,
9535 ring_buffer_size(tr->array_buffer.buffer, 0));
9536
9537 return 0;
9538}
9539
9540static void free_trace_buffer(struct array_buffer *buf)
9541{
9542 if (buf->buffer) {
9543 ring_buffer_free(buf->buffer);
9544 buf->buffer = NULL;
9545 free_percpu(buf->data);
9546 buf->data = NULL;
9547 }
9548}
9549
9550static int allocate_trace_buffers(struct trace_array *tr, int size)
9551{
9552 int ret;
9553
9554 ret = allocate_trace_buffer(tr, &tr->array_buffer, size);
9555 if (ret)
9556 return ret;
9557
9558#ifdef CONFIG_TRACER_MAX_TRACE
9559 ret = allocate_trace_buffer(tr, &tr->max_buffer,
9560 allocate_snapshot ? size : 1);
9561 if (MEM_FAIL(ret, "Failed to allocate trace buffer\n")) {
9562 free_trace_buffer(&tr->array_buffer);
9563 return -ENOMEM;
9564 }
9565 tr->allocated_snapshot = allocate_snapshot;
9566
9567 allocate_snapshot = false;
9568#endif
9569
9570 return 0;
9571}
9572
9573static void free_trace_buffers(struct trace_array *tr)
9574{
9575 if (!tr)
9576 return;
9577
9578 free_trace_buffer(&tr->array_buffer);
9579
9580#ifdef CONFIG_TRACER_MAX_TRACE
9581 free_trace_buffer(&tr->max_buffer);
9582#endif
9583}
9584
9585static void init_trace_flags_index(struct trace_array *tr)
9586{
9587 int i;
9588
9589 /* Used by the trace options files */
9590 for (i = 0; i < TRACE_FLAGS_MAX_SIZE; i++)
9591 tr->trace_flags_index[i] = i;
9592}
9593
9594static void __update_tracer_options(struct trace_array *tr)
9595{
9596 struct tracer *t;
9597
9598 for (t = trace_types; t; t = t->next)
9599 add_tracer_options(tr, t);
9600}
9601
9602static void update_tracer_options(struct trace_array *tr)
9603{
9604 mutex_lock(&trace_types_lock);
9605 tracer_options_updated = true;
9606 __update_tracer_options(tr);
9607 mutex_unlock(&trace_types_lock);
9608}
9609
9610/* Must have trace_types_lock held */
9611struct trace_array *trace_array_find(const char *instance)
9612{
9613 struct trace_array *tr, *found = NULL;
9614
9615 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
9616 if (tr->name && strcmp(tr->name, instance) == 0) {
9617 found = tr;
9618 break;
9619 }
9620 }
9621
9622 return found;
9623}
9624
9625struct trace_array *trace_array_find_get(const char *instance)
9626{
9627 struct trace_array *tr;
9628
9629 mutex_lock(&trace_types_lock);
9630 tr = trace_array_find(instance);
9631 if (tr)
9632 tr->ref++;
9633 mutex_unlock(&trace_types_lock);
9634
9635 return tr;
9636}
9637
9638static int trace_array_create_dir(struct trace_array *tr)
9639{
9640 int ret;
9641
9642 tr->dir = tracefs_create_dir(tr->name, trace_instance_dir);
9643 if (!tr->dir)
9644 return -EINVAL;
9645
9646 ret = event_trace_add_tracer(tr->dir, tr);
9647 if (ret) {
9648 tracefs_remove(tr->dir);
9649 return ret;
9650 }
9651
9652 init_tracer_tracefs(tr, tr->dir);
9653 __update_tracer_options(tr);
9654
9655 return ret;
9656}
9657
9658static struct trace_array *
9659trace_array_create_systems(const char *name, const char *systems)
9660{
9661 struct trace_array *tr;
9662 int ret;
9663
9664 ret = -ENOMEM;
9665 tr = kzalloc(sizeof(*tr), GFP_KERNEL);
9666 if (!tr)
9667 return ERR_PTR(ret);
9668
9669 tr->name = kstrdup(name, GFP_KERNEL);
9670 if (!tr->name)
9671 goto out_free_tr;
9672
9673 if (!alloc_cpumask_var(&tr->tracing_cpumask, GFP_KERNEL))
9674 goto out_free_tr;
9675
9676 if (!zalloc_cpumask_var(&tr->pipe_cpumask, GFP_KERNEL))
9677 goto out_free_tr;
9678
9679 if (systems) {
9680 tr->system_names = kstrdup_const(systems, GFP_KERNEL);
9681 if (!tr->system_names)
9682 goto out_free_tr;
9683 }
9684
9685 tr->trace_flags = global_trace.trace_flags & ~ZEROED_TRACE_FLAGS;
9686
9687 cpumask_copy(tr->tracing_cpumask, cpu_all_mask);
9688
9689 raw_spin_lock_init(&tr->start_lock);
9690
9691 tr->max_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
9692
9693 tr->current_trace = &nop_trace;
9694
9695 INIT_LIST_HEAD(&tr->systems);
9696 INIT_LIST_HEAD(&tr->events);
9697 INIT_LIST_HEAD(&tr->hist_vars);
9698 INIT_LIST_HEAD(&tr->err_log);
9699
9700 if (allocate_trace_buffers(tr, trace_buf_size) < 0)
9701 goto out_free_tr;
9702
9703 /* The ring buffer is defaultly expanded */
9704 trace_set_ring_buffer_expanded(tr);
9705
9706 if (ftrace_allocate_ftrace_ops(tr) < 0)
9707 goto out_free_tr;
9708
9709 ftrace_init_trace_array(tr);
9710
9711 init_trace_flags_index(tr);
9712
9713 if (trace_instance_dir) {
9714 ret = trace_array_create_dir(tr);
9715 if (ret)
9716 goto out_free_tr;
9717 } else
9718 __trace_early_add_events(tr);
9719
9720 list_add(&tr->list, &ftrace_trace_arrays);
9721
9722 tr->ref++;
9723
9724 return tr;
9725
9726 out_free_tr:
9727 ftrace_free_ftrace_ops(tr);
9728 free_trace_buffers(tr);
9729 free_cpumask_var(tr->pipe_cpumask);
9730 free_cpumask_var(tr->tracing_cpumask);
9731 kfree_const(tr->system_names);
9732 kfree(tr->name);
9733 kfree(tr);
9734
9735 return ERR_PTR(ret);
9736}
9737
9738static struct trace_array *trace_array_create(const char *name)
9739{
9740 return trace_array_create_systems(name, NULL);
9741}
9742
9743static int instance_mkdir(const char *name)
9744{
9745 struct trace_array *tr;
9746 int ret;
9747
9748 mutex_lock(&event_mutex);
9749 mutex_lock(&trace_types_lock);
9750
9751 ret = -EEXIST;
9752 if (trace_array_find(name))
9753 goto out_unlock;
9754
9755 tr = trace_array_create(name);
9756
9757 ret = PTR_ERR_OR_ZERO(tr);
9758
9759out_unlock:
9760 mutex_unlock(&trace_types_lock);
9761 mutex_unlock(&event_mutex);
9762 return ret;
9763}
9764
9765/**
9766 * trace_array_get_by_name - Create/Lookup a trace array, given its name.
9767 * @name: The name of the trace array to be looked up/created.
9768 * @systems: A list of systems to create event directories for (NULL for all)
9769 *
9770 * Returns pointer to trace array with given name.
9771 * NULL, if it cannot be created.
9772 *
9773 * NOTE: This function increments the reference counter associated with the
9774 * trace array returned. This makes sure it cannot be freed while in use.
9775 * Use trace_array_put() once the trace array is no longer needed.
9776 * If the trace_array is to be freed, trace_array_destroy() needs to
9777 * be called after the trace_array_put(), or simply let user space delete
9778 * it from the tracefs instances directory. But until the
9779 * trace_array_put() is called, user space can not delete it.
9780 *
9781 */
9782struct trace_array *trace_array_get_by_name(const char *name, const char *systems)
9783{
9784 struct trace_array *tr;
9785
9786 mutex_lock(&event_mutex);
9787 mutex_lock(&trace_types_lock);
9788
9789 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
9790 if (tr->name && strcmp(tr->name, name) == 0)
9791 goto out_unlock;
9792 }
9793
9794 tr = trace_array_create_systems(name, systems);
9795
9796 if (IS_ERR(tr))
9797 tr = NULL;
9798out_unlock:
9799 if (tr)
9800 tr->ref++;
9801
9802 mutex_unlock(&trace_types_lock);
9803 mutex_unlock(&event_mutex);
9804 return tr;
9805}
9806EXPORT_SYMBOL_GPL(trace_array_get_by_name);
9807
9808static int __remove_instance(struct trace_array *tr)
9809{
9810 int i;
9811
9812 /* Reference counter for a newly created trace array = 1. */
9813 if (tr->ref > 1 || (tr->current_trace && tr->trace_ref))
9814 return -EBUSY;
9815
9816 list_del(&tr->list);
9817
9818 /* Disable all the flags that were enabled coming in */
9819 for (i = 0; i < TRACE_FLAGS_MAX_SIZE; i++) {
9820 if ((1 << i) & ZEROED_TRACE_FLAGS)
9821 set_tracer_flag(tr, 1 << i, 0);
9822 }
9823
9824 tracing_set_nop(tr);
9825 clear_ftrace_function_probes(tr);
9826 event_trace_del_tracer(tr);
9827 ftrace_clear_pids(tr);
9828 ftrace_destroy_function_files(tr);
9829 tracefs_remove(tr->dir);
9830 free_percpu(tr->last_func_repeats);
9831 free_trace_buffers(tr);
9832 clear_tracing_err_log(tr);
9833
9834 for (i = 0; i < tr->nr_topts; i++) {
9835 kfree(tr->topts[i].topts);
9836 }
9837 kfree(tr->topts);
9838
9839 free_cpumask_var(tr->pipe_cpumask);
9840 free_cpumask_var(tr->tracing_cpumask);
9841 kfree_const(tr->system_names);
9842 kfree(tr->name);
9843 kfree(tr);
9844
9845 return 0;
9846}
9847
9848int trace_array_destroy(struct trace_array *this_tr)
9849{
9850 struct trace_array *tr;
9851 int ret;
9852
9853 if (!this_tr)
9854 return -EINVAL;
9855
9856 mutex_lock(&event_mutex);
9857 mutex_lock(&trace_types_lock);
9858
9859 ret = -ENODEV;
9860
9861 /* Making sure trace array exists before destroying it. */
9862 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
9863 if (tr == this_tr) {
9864 ret = __remove_instance(tr);
9865 break;
9866 }
9867 }
9868
9869 mutex_unlock(&trace_types_lock);
9870 mutex_unlock(&event_mutex);
9871
9872 return ret;
9873}
9874EXPORT_SYMBOL_GPL(trace_array_destroy);
9875
9876static int instance_rmdir(const char *name)
9877{
9878 struct trace_array *tr;
9879 int ret;
9880
9881 mutex_lock(&event_mutex);
9882 mutex_lock(&trace_types_lock);
9883
9884 ret = -ENODEV;
9885 tr = trace_array_find(name);
9886 if (tr)
9887 ret = __remove_instance(tr);
9888
9889 mutex_unlock(&trace_types_lock);
9890 mutex_unlock(&event_mutex);
9891
9892 return ret;
9893}
9894
9895static __init void create_trace_instances(struct dentry *d_tracer)
9896{
9897 struct trace_array *tr;
9898
9899 trace_instance_dir = tracefs_create_instance_dir("instances", d_tracer,
9900 instance_mkdir,
9901 instance_rmdir);
9902 if (MEM_FAIL(!trace_instance_dir, "Failed to create instances directory\n"))
9903 return;
9904
9905 mutex_lock(&event_mutex);
9906 mutex_lock(&trace_types_lock);
9907
9908 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
9909 if (!tr->name)
9910 continue;
9911 if (MEM_FAIL(trace_array_create_dir(tr) < 0,
9912 "Failed to create instance directory\n"))
9913 break;
9914 }
9915
9916 mutex_unlock(&trace_types_lock);
9917 mutex_unlock(&event_mutex);
9918}
9919
9920static void
9921init_tracer_tracefs(struct trace_array *tr, struct dentry *d_tracer)
9922{
9923 int cpu;
9924
9925 trace_create_file("available_tracers", TRACE_MODE_READ, d_tracer,
9926 tr, &show_traces_fops);
9927
9928 trace_create_file("current_tracer", TRACE_MODE_WRITE, d_tracer,
9929 tr, &set_tracer_fops);
9930
9931 trace_create_file("tracing_cpumask", TRACE_MODE_WRITE, d_tracer,
9932 tr, &tracing_cpumask_fops);
9933
9934 trace_create_file("trace_options", TRACE_MODE_WRITE, d_tracer,
9935 tr, &tracing_iter_fops);
9936
9937 trace_create_file("trace", TRACE_MODE_WRITE, d_tracer,
9938 tr, &tracing_fops);
9939
9940 trace_create_file("trace_pipe", TRACE_MODE_READ, d_tracer,
9941 tr, &tracing_pipe_fops);
9942
9943 trace_create_file("buffer_size_kb", TRACE_MODE_WRITE, d_tracer,
9944 tr, &tracing_entries_fops);
9945
9946 trace_create_file("buffer_total_size_kb", TRACE_MODE_READ, d_tracer,
9947 tr, &tracing_total_entries_fops);
9948
9949 trace_create_file("free_buffer", 0200, d_tracer,
9950 tr, &tracing_free_buffer_fops);
9951
9952 trace_create_file("trace_marker", 0220, d_tracer,
9953 tr, &tracing_mark_fops);
9954
9955 tr->trace_marker_file = __find_event_file(tr, "ftrace", "print");
9956
9957 trace_create_file("trace_marker_raw", 0220, d_tracer,
9958 tr, &tracing_mark_raw_fops);
9959
9960 trace_create_file("trace_clock", TRACE_MODE_WRITE, d_tracer, tr,
9961 &trace_clock_fops);
9962
9963 trace_create_file("tracing_on", TRACE_MODE_WRITE, d_tracer,
9964 tr, &rb_simple_fops);
9965
9966 trace_create_file("timestamp_mode", TRACE_MODE_READ, d_tracer, tr,
9967 &trace_time_stamp_mode_fops);
9968
9969 tr->buffer_percent = 50;
9970
9971 trace_create_file("buffer_percent", TRACE_MODE_WRITE, d_tracer,
9972 tr, &buffer_percent_fops);
9973
9974 trace_create_file("buffer_subbuf_size_kb", TRACE_MODE_WRITE, d_tracer,
9975 tr, &buffer_subbuf_size_fops);
9976
9977 create_trace_options_dir(tr);
9978
9979#ifdef CONFIG_TRACER_MAX_TRACE
9980 trace_create_maxlat_file(tr, d_tracer);
9981#endif
9982
9983 if (ftrace_create_function_files(tr, d_tracer))
9984 MEM_FAIL(1, "Could not allocate function filter files");
9985
9986#ifdef CONFIG_TRACER_SNAPSHOT
9987 trace_create_file("snapshot", TRACE_MODE_WRITE, d_tracer,
9988 tr, &snapshot_fops);
9989#endif
9990
9991 trace_create_file("error_log", TRACE_MODE_WRITE, d_tracer,
9992 tr, &tracing_err_log_fops);
9993
9994 for_each_tracing_cpu(cpu)
9995 tracing_init_tracefs_percpu(tr, cpu);
9996
9997 ftrace_init_tracefs(tr, d_tracer);
9998}
9999
10000static struct vfsmount *trace_automount(struct dentry *mntpt, void *ingore)
10001{
10002 struct vfsmount *mnt;
10003 struct file_system_type *type;
10004
10005 /*
10006 * To maintain backward compatibility for tools that mount
10007 * debugfs to get to the tracing facility, tracefs is automatically
10008 * mounted to the debugfs/tracing directory.
10009 */
10010 type = get_fs_type("tracefs");
10011 if (!type)
10012 return NULL;
10013 mnt = vfs_submount(mntpt, type, "tracefs", NULL);
10014 put_filesystem(type);
10015 if (IS_ERR(mnt))
10016 return NULL;
10017 mntget(mnt);
10018
10019 return mnt;
10020}
10021
10022/**
10023 * tracing_init_dentry - initialize top level trace array
10024 *
10025 * This is called when creating files or directories in the tracing
10026 * directory. It is called via fs_initcall() by any of the boot up code
10027 * and expects to return the dentry of the top level tracing directory.
10028 */
10029int tracing_init_dentry(void)
10030{
10031 struct trace_array *tr = &global_trace;
10032
10033 if (security_locked_down(LOCKDOWN_TRACEFS)) {
10034 pr_warn("Tracing disabled due to lockdown\n");
10035 return -EPERM;
10036 }
10037
10038 /* The top level trace array uses NULL as parent */
10039 if (tr->dir)
10040 return 0;
10041
10042 if (WARN_ON(!tracefs_initialized()))
10043 return -ENODEV;
10044
10045 /*
10046 * As there may still be users that expect the tracing
10047 * files to exist in debugfs/tracing, we must automount
10048 * the tracefs file system there, so older tools still
10049 * work with the newer kernel.
10050 */
10051 tr->dir = debugfs_create_automount("tracing", NULL,
10052 trace_automount, NULL);
10053
10054 return 0;
10055}
10056
10057extern struct trace_eval_map *__start_ftrace_eval_maps[];
10058extern struct trace_eval_map *__stop_ftrace_eval_maps[];
10059
10060static struct workqueue_struct *eval_map_wq __initdata;
10061static struct work_struct eval_map_work __initdata;
10062static struct work_struct tracerfs_init_work __initdata;
10063
10064static void __init eval_map_work_func(struct work_struct *work)
10065{
10066 int len;
10067
10068 len = __stop_ftrace_eval_maps - __start_ftrace_eval_maps;
10069 trace_insert_eval_map(NULL, __start_ftrace_eval_maps, len);
10070}
10071
10072static int __init trace_eval_init(void)
10073{
10074 INIT_WORK(&eval_map_work, eval_map_work_func);
10075
10076 eval_map_wq = alloc_workqueue("eval_map_wq", WQ_UNBOUND, 0);
10077 if (!eval_map_wq) {
10078 pr_err("Unable to allocate eval_map_wq\n");
10079 /* Do work here */
10080 eval_map_work_func(&eval_map_work);
10081 return -ENOMEM;
10082 }
10083
10084 queue_work(eval_map_wq, &eval_map_work);
10085 return 0;
10086}
10087
10088subsys_initcall(trace_eval_init);
10089
10090static int __init trace_eval_sync(void)
10091{
10092 /* Make sure the eval map updates are finished */
10093 if (eval_map_wq)
10094 destroy_workqueue(eval_map_wq);
10095 return 0;
10096}
10097
10098late_initcall_sync(trace_eval_sync);
10099
10100
10101#ifdef CONFIG_MODULES
10102static void trace_module_add_evals(struct module *mod)
10103{
10104 if (!mod->num_trace_evals)
10105 return;
10106
10107 /*
10108 * Modules with bad taint do not have events created, do
10109 * not bother with enums either.
10110 */
10111 if (trace_module_has_bad_taint(mod))
10112 return;
10113
10114 trace_insert_eval_map(mod, mod->trace_evals, mod->num_trace_evals);
10115}
10116
10117#ifdef CONFIG_TRACE_EVAL_MAP_FILE
10118static void trace_module_remove_evals(struct module *mod)
10119{
10120 union trace_eval_map_item *map;
10121 union trace_eval_map_item **last = &trace_eval_maps;
10122
10123 if (!mod->num_trace_evals)
10124 return;
10125
10126 mutex_lock(&trace_eval_mutex);
10127
10128 map = trace_eval_maps;
10129
10130 while (map) {
10131 if (map->head.mod == mod)
10132 break;
10133 map = trace_eval_jmp_to_tail(map);
10134 last = &map->tail.next;
10135 map = map->tail.next;
10136 }
10137 if (!map)
10138 goto out;
10139
10140 *last = trace_eval_jmp_to_tail(map)->tail.next;
10141 kfree(map);
10142 out:
10143 mutex_unlock(&trace_eval_mutex);
10144}
10145#else
10146static inline void trace_module_remove_evals(struct module *mod) { }
10147#endif /* CONFIG_TRACE_EVAL_MAP_FILE */
10148
10149static int trace_module_notify(struct notifier_block *self,
10150 unsigned long val, void *data)
10151{
10152 struct module *mod = data;
10153
10154 switch (val) {
10155 case MODULE_STATE_COMING:
10156 trace_module_add_evals(mod);
10157 break;
10158 case MODULE_STATE_GOING:
10159 trace_module_remove_evals(mod);
10160 break;
10161 }
10162
10163 return NOTIFY_OK;
10164}
10165
10166static struct notifier_block trace_module_nb = {
10167 .notifier_call = trace_module_notify,
10168 .priority = 0,
10169};
10170#endif /* CONFIG_MODULES */
10171
10172static __init void tracer_init_tracefs_work_func(struct work_struct *work)
10173{
10174
10175 event_trace_init();
10176
10177 init_tracer_tracefs(&global_trace, NULL);
10178 ftrace_init_tracefs_toplevel(&global_trace, NULL);
10179
10180 trace_create_file("tracing_thresh", TRACE_MODE_WRITE, NULL,
10181 &global_trace, &tracing_thresh_fops);
10182
10183 trace_create_file("README", TRACE_MODE_READ, NULL,
10184 NULL, &tracing_readme_fops);
10185
10186 trace_create_file("saved_cmdlines", TRACE_MODE_READ, NULL,
10187 NULL, &tracing_saved_cmdlines_fops);
10188
10189 trace_create_file("saved_cmdlines_size", TRACE_MODE_WRITE, NULL,
10190 NULL, &tracing_saved_cmdlines_size_fops);
10191
10192 trace_create_file("saved_tgids", TRACE_MODE_READ, NULL,
10193 NULL, &tracing_saved_tgids_fops);
10194
10195 trace_create_eval_file(NULL);
10196
10197#ifdef CONFIG_MODULES
10198 register_module_notifier(&trace_module_nb);
10199#endif
10200
10201#ifdef CONFIG_DYNAMIC_FTRACE
10202 trace_create_file("dyn_ftrace_total_info", TRACE_MODE_READ, NULL,
10203 NULL, &tracing_dyn_info_fops);
10204#endif
10205
10206 create_trace_instances(NULL);
10207
10208 update_tracer_options(&global_trace);
10209}
10210
10211static __init int tracer_init_tracefs(void)
10212{
10213 int ret;
10214
10215 trace_access_lock_init();
10216
10217 ret = tracing_init_dentry();
10218 if (ret)
10219 return 0;
10220
10221 if (eval_map_wq) {
10222 INIT_WORK(&tracerfs_init_work, tracer_init_tracefs_work_func);
10223 queue_work(eval_map_wq, &tracerfs_init_work);
10224 } else {
10225 tracer_init_tracefs_work_func(NULL);
10226 }
10227
10228 rv_init_interface();
10229
10230 return 0;
10231}
10232
10233fs_initcall(tracer_init_tracefs);
10234
10235static int trace_die_panic_handler(struct notifier_block *self,
10236 unsigned long ev, void *unused);
10237
10238static struct notifier_block trace_panic_notifier = {
10239 .notifier_call = trace_die_panic_handler,
10240 .priority = INT_MAX - 1,
10241};
10242
10243static struct notifier_block trace_die_notifier = {
10244 .notifier_call = trace_die_panic_handler,
10245 .priority = INT_MAX - 1,
10246};
10247
10248/*
10249 * The idea is to execute the following die/panic callback early, in order
10250 * to avoid showing irrelevant information in the trace (like other panic
10251 * notifier functions); we are the 2nd to run, after hung_task/rcu_stall
10252 * warnings get disabled (to prevent potential log flooding).
10253 */
10254static int trace_die_panic_handler(struct notifier_block *self,
10255 unsigned long ev, void *unused)
10256{
10257 if (!ftrace_dump_on_oops)
10258 return NOTIFY_DONE;
10259
10260 /* The die notifier requires DIE_OOPS to trigger */
10261 if (self == &trace_die_notifier && ev != DIE_OOPS)
10262 return NOTIFY_DONE;
10263
10264 ftrace_dump(ftrace_dump_on_oops);
10265
10266 return NOTIFY_DONE;
10267}
10268
10269/*
10270 * printk is set to max of 1024, we really don't need it that big.
10271 * Nothing should be printing 1000 characters anyway.
10272 */
10273#define TRACE_MAX_PRINT 1000
10274
10275/*
10276 * Define here KERN_TRACE so that we have one place to modify
10277 * it if we decide to change what log level the ftrace dump
10278 * should be at.
10279 */
10280#define KERN_TRACE KERN_EMERG
10281
10282void
10283trace_printk_seq(struct trace_seq *s)
10284{
10285 /* Probably should print a warning here. */
10286 if (s->seq.len >= TRACE_MAX_PRINT)
10287 s->seq.len = TRACE_MAX_PRINT;
10288
10289 /*
10290 * More paranoid code. Although the buffer size is set to
10291 * PAGE_SIZE, and TRACE_MAX_PRINT is 1000, this is just
10292 * an extra layer of protection.
10293 */
10294 if (WARN_ON_ONCE(s->seq.len >= s->seq.size))
10295 s->seq.len = s->seq.size - 1;
10296
10297 /* should be zero ended, but we are paranoid. */
10298 s->buffer[s->seq.len] = 0;
10299
10300 printk(KERN_TRACE "%s", s->buffer);
10301
10302 trace_seq_init(s);
10303}
10304
10305void trace_init_global_iter(struct trace_iterator *iter)
10306{
10307 iter->tr = &global_trace;
10308 iter->trace = iter->tr->current_trace;
10309 iter->cpu_file = RING_BUFFER_ALL_CPUS;
10310 iter->array_buffer = &global_trace.array_buffer;
10311
10312 if (iter->trace && iter->trace->open)
10313 iter->trace->open(iter);
10314
10315 /* Annotate start of buffers if we had overruns */
10316 if (ring_buffer_overruns(iter->array_buffer->buffer))
10317 iter->iter_flags |= TRACE_FILE_ANNOTATE;
10318
10319 /* Output in nanoseconds only if we are using a clock in nanoseconds. */
10320 if (trace_clocks[iter->tr->clock_id].in_ns)
10321 iter->iter_flags |= TRACE_FILE_TIME_IN_NS;
10322
10323 /* Can not use kmalloc for iter.temp and iter.fmt */
10324 iter->temp = static_temp_buf;
10325 iter->temp_size = STATIC_TEMP_BUF_SIZE;
10326 iter->fmt = static_fmt_buf;
10327 iter->fmt_size = STATIC_FMT_BUF_SIZE;
10328}
10329
10330void ftrace_dump(enum ftrace_dump_mode oops_dump_mode)
10331{
10332 /* use static because iter can be a bit big for the stack */
10333 static struct trace_iterator iter;
10334 static atomic_t dump_running;
10335 struct trace_array *tr = &global_trace;
10336 unsigned int old_userobj;
10337 unsigned long flags;
10338 int cnt = 0, cpu;
10339
10340 /* Only allow one dump user at a time. */
10341 if (atomic_inc_return(&dump_running) != 1) {
10342 atomic_dec(&dump_running);
10343 return;
10344 }
10345
10346 /*
10347 * Always turn off tracing when we dump.
10348 * We don't need to show trace output of what happens
10349 * between multiple crashes.
10350 *
10351 * If the user does a sysrq-z, then they can re-enable
10352 * tracing with echo 1 > tracing_on.
10353 */
10354 tracing_off();
10355
10356 local_irq_save(flags);
10357
10358 /* Simulate the iterator */
10359 trace_init_global_iter(&iter);
10360
10361 for_each_tracing_cpu(cpu) {
10362 atomic_inc(&per_cpu_ptr(iter.array_buffer->data, cpu)->disabled);
10363 }
10364
10365 old_userobj = tr->trace_flags & TRACE_ITER_SYM_USEROBJ;
10366
10367 /* don't look at user memory in panic mode */
10368 tr->trace_flags &= ~TRACE_ITER_SYM_USEROBJ;
10369
10370 switch (oops_dump_mode) {
10371 case DUMP_ALL:
10372 iter.cpu_file = RING_BUFFER_ALL_CPUS;
10373 break;
10374 case DUMP_ORIG:
10375 iter.cpu_file = raw_smp_processor_id();
10376 break;
10377 case DUMP_NONE:
10378 goto out_enable;
10379 default:
10380 printk(KERN_TRACE "Bad dumping mode, switching to all CPUs dump\n");
10381 iter.cpu_file = RING_BUFFER_ALL_CPUS;
10382 }
10383
10384 printk(KERN_TRACE "Dumping ftrace buffer:\n");
10385
10386 /* Did function tracer already get disabled? */
10387 if (ftrace_is_dead()) {
10388 printk("# WARNING: FUNCTION TRACING IS CORRUPTED\n");
10389 printk("# MAY BE MISSING FUNCTION EVENTS\n");
10390 }
10391
10392 /*
10393 * We need to stop all tracing on all CPUS to read
10394 * the next buffer. This is a bit expensive, but is
10395 * not done often. We fill all what we can read,
10396 * and then release the locks again.
10397 */
10398
10399 while (!trace_empty(&iter)) {
10400
10401 if (!cnt)
10402 printk(KERN_TRACE "---------------------------------\n");
10403
10404 cnt++;
10405
10406 trace_iterator_reset(&iter);
10407 iter.iter_flags |= TRACE_FILE_LAT_FMT;
10408
10409 if (trace_find_next_entry_inc(&iter) != NULL) {
10410 int ret;
10411
10412 ret = print_trace_line(&iter);
10413 if (ret != TRACE_TYPE_NO_CONSUME)
10414 trace_consume(&iter);
10415 }
10416 touch_nmi_watchdog();
10417
10418 trace_printk_seq(&iter.seq);
10419 }
10420
10421 if (!cnt)
10422 printk(KERN_TRACE " (ftrace buffer empty)\n");
10423 else
10424 printk(KERN_TRACE "---------------------------------\n");
10425
10426 out_enable:
10427 tr->trace_flags |= old_userobj;
10428
10429 for_each_tracing_cpu(cpu) {
10430 atomic_dec(&per_cpu_ptr(iter.array_buffer->data, cpu)->disabled);
10431 }
10432 atomic_dec(&dump_running);
10433 local_irq_restore(flags);
10434}
10435EXPORT_SYMBOL_GPL(ftrace_dump);
10436
10437#define WRITE_BUFSIZE 4096
10438
10439ssize_t trace_parse_run_command(struct file *file, const char __user *buffer,
10440 size_t count, loff_t *ppos,
10441 int (*createfn)(const char *))
10442{
10443 char *kbuf, *buf, *tmp;
10444 int ret = 0;
10445 size_t done = 0;
10446 size_t size;
10447
10448 kbuf = kmalloc(WRITE_BUFSIZE, GFP_KERNEL);
10449 if (!kbuf)
10450 return -ENOMEM;
10451
10452 while (done < count) {
10453 size = count - done;
10454
10455 if (size >= WRITE_BUFSIZE)
10456 size = WRITE_BUFSIZE - 1;
10457
10458 if (copy_from_user(kbuf, buffer + done, size)) {
10459 ret = -EFAULT;
10460 goto out;
10461 }
10462 kbuf[size] = '\0';
10463 buf = kbuf;
10464 do {
10465 tmp = strchr(buf, '\n');
10466 if (tmp) {
10467 *tmp = '\0';
10468 size = tmp - buf + 1;
10469 } else {
10470 size = strlen(buf);
10471 if (done + size < count) {
10472 if (buf != kbuf)
10473 break;
10474 /* This can accept WRITE_BUFSIZE - 2 ('\n' + '\0') */
10475 pr_warn("Line length is too long: Should be less than %d\n",
10476 WRITE_BUFSIZE - 2);
10477 ret = -EINVAL;
10478 goto out;
10479 }
10480 }
10481 done += size;
10482
10483 /* Remove comments */
10484 tmp = strchr(buf, '#');
10485
10486 if (tmp)
10487 *tmp = '\0';
10488
10489 ret = createfn(buf);
10490 if (ret)
10491 goto out;
10492 buf += size;
10493
10494 } while (done < count);
10495 }
10496 ret = done;
10497
10498out:
10499 kfree(kbuf);
10500
10501 return ret;
10502}
10503
10504#ifdef CONFIG_TRACER_MAX_TRACE
10505__init static bool tr_needs_alloc_snapshot(const char *name)
10506{
10507 char *test;
10508 int len = strlen(name);
10509 bool ret;
10510
10511 if (!boot_snapshot_index)
10512 return false;
10513
10514 if (strncmp(name, boot_snapshot_info, len) == 0 &&
10515 boot_snapshot_info[len] == '\t')
10516 return true;
10517
10518 test = kmalloc(strlen(name) + 3, GFP_KERNEL);
10519 if (!test)
10520 return false;
10521
10522 sprintf(test, "\t%s\t", name);
10523 ret = strstr(boot_snapshot_info, test) == NULL;
10524 kfree(test);
10525 return ret;
10526}
10527
10528__init static void do_allocate_snapshot(const char *name)
10529{
10530 if (!tr_needs_alloc_snapshot(name))
10531 return;
10532
10533 /*
10534 * When allocate_snapshot is set, the next call to
10535 * allocate_trace_buffers() (called by trace_array_get_by_name())
10536 * will allocate the snapshot buffer. That will alse clear
10537 * this flag.
10538 */
10539 allocate_snapshot = true;
10540}
10541#else
10542static inline void do_allocate_snapshot(const char *name) { }
10543#endif
10544
10545__init static void enable_instances(void)
10546{
10547 struct trace_array *tr;
10548 char *curr_str;
10549 char *str;
10550 char *tok;
10551
10552 /* A tab is always appended */
10553 boot_instance_info[boot_instance_index - 1] = '\0';
10554 str = boot_instance_info;
10555
10556 while ((curr_str = strsep(&str, "\t"))) {
10557
10558 tok = strsep(&curr_str, ",");
10559
10560 if (IS_ENABLED(CONFIG_TRACER_MAX_TRACE))
10561 do_allocate_snapshot(tok);
10562
10563 tr = trace_array_get_by_name(tok, NULL);
10564 if (!tr) {
10565 pr_warn("Failed to create instance buffer %s\n", curr_str);
10566 continue;
10567 }
10568 /* Allow user space to delete it */
10569 trace_array_put(tr);
10570
10571 while ((tok = strsep(&curr_str, ","))) {
10572 early_enable_events(tr, tok, true);
10573 }
10574 }
10575}
10576
10577__init static int tracer_alloc_buffers(void)
10578{
10579 int ring_buf_size;
10580 int ret = -ENOMEM;
10581
10582
10583 if (security_locked_down(LOCKDOWN_TRACEFS)) {
10584 pr_warn("Tracing disabled due to lockdown\n");
10585 return -EPERM;
10586 }
10587
10588 /*
10589 * Make sure we don't accidentally add more trace options
10590 * than we have bits for.
10591 */
10592 BUILD_BUG_ON(TRACE_ITER_LAST_BIT > TRACE_FLAGS_MAX_SIZE);
10593
10594 if (!alloc_cpumask_var(&tracing_buffer_mask, GFP_KERNEL))
10595 goto out;
10596
10597 if (!alloc_cpumask_var(&global_trace.tracing_cpumask, GFP_KERNEL))
10598 goto out_free_buffer_mask;
10599
10600 /* Only allocate trace_printk buffers if a trace_printk exists */
10601 if (&__stop___trace_bprintk_fmt != &__start___trace_bprintk_fmt)
10602 /* Must be called before global_trace.buffer is allocated */
10603 trace_printk_init_buffers();
10604
10605 /* To save memory, keep the ring buffer size to its minimum */
10606 if (global_trace.ring_buffer_expanded)
10607 ring_buf_size = trace_buf_size;
10608 else
10609 ring_buf_size = 1;
10610
10611 cpumask_copy(tracing_buffer_mask, cpu_possible_mask);
10612 cpumask_copy(global_trace.tracing_cpumask, cpu_all_mask);
10613
10614 raw_spin_lock_init(&global_trace.start_lock);
10615
10616 /*
10617 * The prepare callbacks allocates some memory for the ring buffer. We
10618 * don't free the buffer if the CPU goes down. If we were to free
10619 * the buffer, then the user would lose any trace that was in the
10620 * buffer. The memory will be removed once the "instance" is removed.
10621 */
10622 ret = cpuhp_setup_state_multi(CPUHP_TRACE_RB_PREPARE,
10623 "trace/RB:prepare", trace_rb_cpu_prepare,
10624 NULL);
10625 if (ret < 0)
10626 goto out_free_cpumask;
10627 /* Used for event triggers */
10628 ret = -ENOMEM;
10629 temp_buffer = ring_buffer_alloc(PAGE_SIZE, RB_FL_OVERWRITE);
10630 if (!temp_buffer)
10631 goto out_rm_hp_state;
10632
10633 if (trace_create_savedcmd() < 0)
10634 goto out_free_temp_buffer;
10635
10636 if (!zalloc_cpumask_var(&global_trace.pipe_cpumask, GFP_KERNEL))
10637 goto out_free_savedcmd;
10638
10639 /* TODO: make the number of buffers hot pluggable with CPUS */
10640 if (allocate_trace_buffers(&global_trace, ring_buf_size) < 0) {
10641 MEM_FAIL(1, "tracer: failed to allocate ring buffer!\n");
10642 goto out_free_pipe_cpumask;
10643 }
10644 if (global_trace.buffer_disabled)
10645 tracing_off();
10646
10647 if (trace_boot_clock) {
10648 ret = tracing_set_clock(&global_trace, trace_boot_clock);
10649 if (ret < 0)
10650 pr_warn("Trace clock %s not defined, going back to default\n",
10651 trace_boot_clock);
10652 }
10653
10654 /*
10655 * register_tracer() might reference current_trace, so it
10656 * needs to be set before we register anything. This is
10657 * just a bootstrap of current_trace anyway.
10658 */
10659 global_trace.current_trace = &nop_trace;
10660
10661 global_trace.max_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
10662
10663 ftrace_init_global_array_ops(&global_trace);
10664
10665 init_trace_flags_index(&global_trace);
10666
10667 register_tracer(&nop_trace);
10668
10669 /* Function tracing may start here (via kernel command line) */
10670 init_function_trace();
10671
10672 /* All seems OK, enable tracing */
10673 tracing_disabled = 0;
10674
10675 atomic_notifier_chain_register(&panic_notifier_list,
10676 &trace_panic_notifier);
10677
10678 register_die_notifier(&trace_die_notifier);
10679
10680 global_trace.flags = TRACE_ARRAY_FL_GLOBAL;
10681
10682 INIT_LIST_HEAD(&global_trace.systems);
10683 INIT_LIST_HEAD(&global_trace.events);
10684 INIT_LIST_HEAD(&global_trace.hist_vars);
10685 INIT_LIST_HEAD(&global_trace.err_log);
10686 list_add(&global_trace.list, &ftrace_trace_arrays);
10687
10688 apply_trace_boot_options();
10689
10690 register_snapshot_cmd();
10691
10692 test_can_verify();
10693
10694 return 0;
10695
10696out_free_pipe_cpumask:
10697 free_cpumask_var(global_trace.pipe_cpumask);
10698out_free_savedcmd:
10699 free_saved_cmdlines_buffer(savedcmd);
10700out_free_temp_buffer:
10701 ring_buffer_free(temp_buffer);
10702out_rm_hp_state:
10703 cpuhp_remove_multi_state(CPUHP_TRACE_RB_PREPARE);
10704out_free_cpumask:
10705 free_cpumask_var(global_trace.tracing_cpumask);
10706out_free_buffer_mask:
10707 free_cpumask_var(tracing_buffer_mask);
10708out:
10709 return ret;
10710}
10711
10712void __init ftrace_boot_snapshot(void)
10713{
10714#ifdef CONFIG_TRACER_MAX_TRACE
10715 struct trace_array *tr;
10716
10717 if (!snapshot_at_boot)
10718 return;
10719
10720 list_for_each_entry(tr, &ftrace_trace_arrays, list) {
10721 if (!tr->allocated_snapshot)
10722 continue;
10723
10724 tracing_snapshot_instance(tr);
10725 trace_array_puts(tr, "** Boot snapshot taken **\n");
10726 }
10727#endif
10728}
10729
10730void __init early_trace_init(void)
10731{
10732 if (tracepoint_printk) {
10733 tracepoint_print_iter =
10734 kzalloc(sizeof(*tracepoint_print_iter), GFP_KERNEL);
10735 if (MEM_FAIL(!tracepoint_print_iter,
10736 "Failed to allocate trace iterator\n"))
10737 tracepoint_printk = 0;
10738 else
10739 static_key_enable(&tracepoint_printk_key.key);
10740 }
10741 tracer_alloc_buffers();
10742
10743 init_events();
10744}
10745
10746void __init trace_init(void)
10747{
10748 trace_event_init();
10749
10750 if (boot_instance_index)
10751 enable_instances();
10752}
10753
10754__init static void clear_boot_tracer(void)
10755{
10756 /*
10757 * The default tracer at boot buffer is an init section.
10758 * This function is called in lateinit. If we did not
10759 * find the boot tracer, then clear it out, to prevent
10760 * later registration from accessing the buffer that is
10761 * about to be freed.
10762 */
10763 if (!default_bootup_tracer)
10764 return;
10765
10766 printk(KERN_INFO "ftrace bootup tracer '%s' not registered.\n",
10767 default_bootup_tracer);
10768 default_bootup_tracer = NULL;
10769}
10770
10771#ifdef CONFIG_HAVE_UNSTABLE_SCHED_CLOCK
10772__init static void tracing_set_default_clock(void)
10773{
10774 /* sched_clock_stable() is determined in late_initcall */
10775 if (!trace_boot_clock && !sched_clock_stable()) {
10776 if (security_locked_down(LOCKDOWN_TRACEFS)) {
10777 pr_warn("Can not set tracing clock due to lockdown\n");
10778 return;
10779 }
10780
10781 printk(KERN_WARNING
10782 "Unstable clock detected, switching default tracing clock to \"global\"\n"
10783 "If you want to keep using the local clock, then add:\n"
10784 " \"trace_clock=local\"\n"
10785 "on the kernel command line\n");
10786 tracing_set_clock(&global_trace, "global");
10787 }
10788}
10789#else
10790static inline void tracing_set_default_clock(void) { }
10791#endif
10792
10793__init static int late_trace_init(void)
10794{
10795 if (tracepoint_printk && tracepoint_printk_stop_on_boot) {
10796 static_key_disable(&tracepoint_printk_key.key);
10797 tracepoint_printk = 0;
10798 }
10799
10800 tracing_set_default_clock();
10801 clear_boot_tracer();
10802 return 0;
10803}
10804
10805late_initcall_sync(late_trace_init);
1/*
2 * ring buffer based function tracer
3 *
4 * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
5 * Copyright (C) 2008 Ingo Molnar <mingo@redhat.com>
6 *
7 * Originally taken from the RT patch by:
8 * Arnaldo Carvalho de Melo <acme@redhat.com>
9 *
10 * Based on code from the latency_tracer, that is:
11 * Copyright (C) 2004-2006 Ingo Molnar
12 * Copyright (C) 2004 William Lee Irwin III
13 */
14#include <linux/ring_buffer.h>
15#include <generated/utsrelease.h>
16#include <linux/stacktrace.h>
17#include <linux/writeback.h>
18#include <linux/kallsyms.h>
19#include <linux/seq_file.h>
20#include <linux/notifier.h>
21#include <linux/irqflags.h>
22#include <linux/debugfs.h>
23#include <linux/pagemap.h>
24#include <linux/hardirq.h>
25#include <linux/linkage.h>
26#include <linux/uaccess.h>
27#include <linux/kprobes.h>
28#include <linux/ftrace.h>
29#include <linux/module.h>
30#include <linux/percpu.h>
31#include <linux/splice.h>
32#include <linux/kdebug.h>
33#include <linux/string.h>
34#include <linux/rwsem.h>
35#include <linux/slab.h>
36#include <linux/ctype.h>
37#include <linux/init.h>
38#include <linux/poll.h>
39#include <linux/nmi.h>
40#include <linux/fs.h>
41
42#include "trace.h"
43#include "trace_output.h"
44
45/*
46 * On boot up, the ring buffer is set to the minimum size, so that
47 * we do not waste memory on systems that are not using tracing.
48 */
49int ring_buffer_expanded;
50
51/*
52 * We need to change this state when a selftest is running.
53 * A selftest will lurk into the ring-buffer to count the
54 * entries inserted during the selftest although some concurrent
55 * insertions into the ring-buffer such as trace_printk could occurred
56 * at the same time, giving false positive or negative results.
57 */
58static bool __read_mostly tracing_selftest_running;
59
60/*
61 * If a tracer is running, we do not want to run SELFTEST.
62 */
63bool __read_mostly tracing_selftest_disabled;
64
65/* For tracers that don't implement custom flags */
66static struct tracer_opt dummy_tracer_opt[] = {
67 { }
68};
69
70static struct tracer_flags dummy_tracer_flags = {
71 .val = 0,
72 .opts = dummy_tracer_opt
73};
74
75static int dummy_set_flag(u32 old_flags, u32 bit, int set)
76{
77 return 0;
78}
79
80/*
81 * Kill all tracing for good (never come back).
82 * It is initialized to 1 but will turn to zero if the initialization
83 * of the tracer is successful. But that is the only place that sets
84 * this back to zero.
85 */
86static int tracing_disabled = 1;
87
88DEFINE_PER_CPU(int, ftrace_cpu_disabled);
89
90cpumask_var_t __read_mostly tracing_buffer_mask;
91
92/*
93 * ftrace_dump_on_oops - variable to dump ftrace buffer on oops
94 *
95 * If there is an oops (or kernel panic) and the ftrace_dump_on_oops
96 * is set, then ftrace_dump is called. This will output the contents
97 * of the ftrace buffers to the console. This is very useful for
98 * capturing traces that lead to crashes and outputing it to a
99 * serial console.
100 *
101 * It is default off, but you can enable it with either specifying
102 * "ftrace_dump_on_oops" in the kernel command line, or setting
103 * /proc/sys/kernel/ftrace_dump_on_oops
104 * Set 1 if you want to dump buffers of all CPUs
105 * Set 2 if you want to dump the buffer of the CPU that triggered oops
106 */
107
108enum ftrace_dump_mode ftrace_dump_on_oops;
109
110static int tracing_set_tracer(const char *buf);
111
112#define MAX_TRACER_SIZE 100
113static char bootup_tracer_buf[MAX_TRACER_SIZE] __initdata;
114static char *default_bootup_tracer;
115
116static int __init set_cmdline_ftrace(char *str)
117{
118 strncpy(bootup_tracer_buf, str, MAX_TRACER_SIZE);
119 default_bootup_tracer = bootup_tracer_buf;
120 /* We are using ftrace early, expand it */
121 ring_buffer_expanded = 1;
122 return 1;
123}
124__setup("ftrace=", set_cmdline_ftrace);
125
126static int __init set_ftrace_dump_on_oops(char *str)
127{
128 if (*str++ != '=' || !*str) {
129 ftrace_dump_on_oops = DUMP_ALL;
130 return 1;
131 }
132
133 if (!strcmp("orig_cpu", str)) {
134 ftrace_dump_on_oops = DUMP_ORIG;
135 return 1;
136 }
137
138 return 0;
139}
140__setup("ftrace_dump_on_oops", set_ftrace_dump_on_oops);
141
142unsigned long long ns2usecs(cycle_t nsec)
143{
144 nsec += 500;
145 do_div(nsec, 1000);
146 return nsec;
147}
148
149/*
150 * The global_trace is the descriptor that holds the tracing
151 * buffers for the live tracing. For each CPU, it contains
152 * a link list of pages that will store trace entries. The
153 * page descriptor of the pages in the memory is used to hold
154 * the link list by linking the lru item in the page descriptor
155 * to each of the pages in the buffer per CPU.
156 *
157 * For each active CPU there is a data field that holds the
158 * pages for the buffer for that CPU. Each CPU has the same number
159 * of pages allocated for its buffer.
160 */
161static struct trace_array global_trace;
162
163static DEFINE_PER_CPU(struct trace_array_cpu, global_trace_cpu);
164
165int filter_current_check_discard(struct ring_buffer *buffer,
166 struct ftrace_event_call *call, void *rec,
167 struct ring_buffer_event *event)
168{
169 return filter_check_discard(call, rec, buffer, event);
170}
171EXPORT_SYMBOL_GPL(filter_current_check_discard);
172
173cycle_t ftrace_now(int cpu)
174{
175 u64 ts;
176
177 /* Early boot up does not have a buffer yet */
178 if (!global_trace.buffer)
179 return trace_clock_local();
180
181 ts = ring_buffer_time_stamp(global_trace.buffer, cpu);
182 ring_buffer_normalize_time_stamp(global_trace.buffer, cpu, &ts);
183
184 return ts;
185}
186
187/*
188 * The max_tr is used to snapshot the global_trace when a maximum
189 * latency is reached. Some tracers will use this to store a maximum
190 * trace while it continues examining live traces.
191 *
192 * The buffers for the max_tr are set up the same as the global_trace.
193 * When a snapshot is taken, the link list of the max_tr is swapped
194 * with the link list of the global_trace and the buffers are reset for
195 * the global_trace so the tracing can continue.
196 */
197static struct trace_array max_tr;
198
199static DEFINE_PER_CPU(struct trace_array_cpu, max_tr_data);
200
201/* tracer_enabled is used to toggle activation of a tracer */
202static int tracer_enabled = 1;
203
204/**
205 * tracing_is_enabled - return tracer_enabled status
206 *
207 * This function is used by other tracers to know the status
208 * of the tracer_enabled flag. Tracers may use this function
209 * to know if it should enable their features when starting
210 * up. See irqsoff tracer for an example (start_irqsoff_tracer).
211 */
212int tracing_is_enabled(void)
213{
214 return tracer_enabled;
215}
216
217/*
218 * trace_buf_size is the size in bytes that is allocated
219 * for a buffer. Note, the number of bytes is always rounded
220 * to page size.
221 *
222 * This number is purposely set to a low number of 16384.
223 * If the dump on oops happens, it will be much appreciated
224 * to not have to wait for all that output. Anyway this can be
225 * boot time and run time configurable.
226 */
227#define TRACE_BUF_SIZE_DEFAULT 1441792UL /* 16384 * 88 (sizeof(entry)) */
228
229static unsigned long trace_buf_size = TRACE_BUF_SIZE_DEFAULT;
230
231/* trace_types holds a link list of available tracers. */
232static struct tracer *trace_types __read_mostly;
233
234/* current_trace points to the tracer that is currently active */
235static struct tracer *current_trace __read_mostly;
236
237/*
238 * trace_types_lock is used to protect the trace_types list.
239 */
240static DEFINE_MUTEX(trace_types_lock);
241
242/*
243 * serialize the access of the ring buffer
244 *
245 * ring buffer serializes readers, but it is low level protection.
246 * The validity of the events (which returns by ring_buffer_peek() ..etc)
247 * are not protected by ring buffer.
248 *
249 * The content of events may become garbage if we allow other process consumes
250 * these events concurrently:
251 * A) the page of the consumed events may become a normal page
252 * (not reader page) in ring buffer, and this page will be rewrited
253 * by events producer.
254 * B) The page of the consumed events may become a page for splice_read,
255 * and this page will be returned to system.
256 *
257 * These primitives allow multi process access to different cpu ring buffer
258 * concurrently.
259 *
260 * These primitives don't distinguish read-only and read-consume access.
261 * Multi read-only access are also serialized.
262 */
263
264#ifdef CONFIG_SMP
265static DECLARE_RWSEM(all_cpu_access_lock);
266static DEFINE_PER_CPU(struct mutex, cpu_access_lock);
267
268static inline void trace_access_lock(int cpu)
269{
270 if (cpu == TRACE_PIPE_ALL_CPU) {
271 /* gain it for accessing the whole ring buffer. */
272 down_write(&all_cpu_access_lock);
273 } else {
274 /* gain it for accessing a cpu ring buffer. */
275
276 /* Firstly block other trace_access_lock(TRACE_PIPE_ALL_CPU). */
277 down_read(&all_cpu_access_lock);
278
279 /* Secondly block other access to this @cpu ring buffer. */
280 mutex_lock(&per_cpu(cpu_access_lock, cpu));
281 }
282}
283
284static inline void trace_access_unlock(int cpu)
285{
286 if (cpu == TRACE_PIPE_ALL_CPU) {
287 up_write(&all_cpu_access_lock);
288 } else {
289 mutex_unlock(&per_cpu(cpu_access_lock, cpu));
290 up_read(&all_cpu_access_lock);
291 }
292}
293
294static inline void trace_access_lock_init(void)
295{
296 int cpu;
297
298 for_each_possible_cpu(cpu)
299 mutex_init(&per_cpu(cpu_access_lock, cpu));
300}
301
302#else
303
304static DEFINE_MUTEX(access_lock);
305
306static inline void trace_access_lock(int cpu)
307{
308 (void)cpu;
309 mutex_lock(&access_lock);
310}
311
312static inline void trace_access_unlock(int cpu)
313{
314 (void)cpu;
315 mutex_unlock(&access_lock);
316}
317
318static inline void trace_access_lock_init(void)
319{
320}
321
322#endif
323
324/* trace_wait is a waitqueue for tasks blocked on trace_poll */
325static DECLARE_WAIT_QUEUE_HEAD(trace_wait);
326
327/* trace_flags holds trace_options default values */
328unsigned long trace_flags = TRACE_ITER_PRINT_PARENT | TRACE_ITER_PRINTK |
329 TRACE_ITER_ANNOTATE | TRACE_ITER_CONTEXT_INFO | TRACE_ITER_SLEEP_TIME |
330 TRACE_ITER_GRAPH_TIME | TRACE_ITER_RECORD_CMD | TRACE_ITER_OVERWRITE |
331 TRACE_ITER_IRQ_INFO;
332
333static int trace_stop_count;
334static DEFINE_RAW_SPINLOCK(tracing_start_lock);
335
336static void wakeup_work_handler(struct work_struct *work)
337{
338 wake_up(&trace_wait);
339}
340
341static DECLARE_DELAYED_WORK(wakeup_work, wakeup_work_handler);
342
343/**
344 * tracing_on - enable tracing buffers
345 *
346 * This function enables tracing buffers that may have been
347 * disabled with tracing_off.
348 */
349void tracing_on(void)
350{
351 if (global_trace.buffer)
352 ring_buffer_record_on(global_trace.buffer);
353 /*
354 * This flag is only looked at when buffers haven't been
355 * allocated yet. We don't really care about the race
356 * between setting this flag and actually turning
357 * on the buffer.
358 */
359 global_trace.buffer_disabled = 0;
360}
361EXPORT_SYMBOL_GPL(tracing_on);
362
363/**
364 * tracing_off - turn off tracing buffers
365 *
366 * This function stops the tracing buffers from recording data.
367 * It does not disable any overhead the tracers themselves may
368 * be causing. This function simply causes all recording to
369 * the ring buffers to fail.
370 */
371void tracing_off(void)
372{
373 if (global_trace.buffer)
374 ring_buffer_record_off(global_trace.buffer);
375 /*
376 * This flag is only looked at when buffers haven't been
377 * allocated yet. We don't really care about the race
378 * between setting this flag and actually turning
379 * on the buffer.
380 */
381 global_trace.buffer_disabled = 1;
382}
383EXPORT_SYMBOL_GPL(tracing_off);
384
385/**
386 * tracing_is_on - show state of ring buffers enabled
387 */
388int tracing_is_on(void)
389{
390 if (global_trace.buffer)
391 return ring_buffer_record_is_on(global_trace.buffer);
392 return !global_trace.buffer_disabled;
393}
394EXPORT_SYMBOL_GPL(tracing_is_on);
395
396/**
397 * trace_wake_up - wake up tasks waiting for trace input
398 *
399 * Schedules a delayed work to wake up any task that is blocked on the
400 * trace_wait queue. These is used with trace_poll for tasks polling the
401 * trace.
402 */
403void trace_wake_up(void)
404{
405 const unsigned long delay = msecs_to_jiffies(2);
406
407 if (trace_flags & TRACE_ITER_BLOCK)
408 return;
409 schedule_delayed_work(&wakeup_work, delay);
410}
411
412static int __init set_buf_size(char *str)
413{
414 unsigned long buf_size;
415
416 if (!str)
417 return 0;
418 buf_size = memparse(str, &str);
419 /* nr_entries can not be zero */
420 if (buf_size == 0)
421 return 0;
422 trace_buf_size = buf_size;
423 return 1;
424}
425__setup("trace_buf_size=", set_buf_size);
426
427static int __init set_tracing_thresh(char *str)
428{
429 unsigned long threshhold;
430 int ret;
431
432 if (!str)
433 return 0;
434 ret = strict_strtoul(str, 0, &threshhold);
435 if (ret < 0)
436 return 0;
437 tracing_thresh = threshhold * 1000;
438 return 1;
439}
440__setup("tracing_thresh=", set_tracing_thresh);
441
442unsigned long nsecs_to_usecs(unsigned long nsecs)
443{
444 return nsecs / 1000;
445}
446
447/* These must match the bit postions in trace_iterator_flags */
448static const char *trace_options[] = {
449 "print-parent",
450 "sym-offset",
451 "sym-addr",
452 "verbose",
453 "raw",
454 "hex",
455 "bin",
456 "block",
457 "stacktrace",
458 "trace_printk",
459 "ftrace_preempt",
460 "branch",
461 "annotate",
462 "userstacktrace",
463 "sym-userobj",
464 "printk-msg-only",
465 "context-info",
466 "latency-format",
467 "sleep-time",
468 "graph-time",
469 "record-cmd",
470 "overwrite",
471 "disable_on_free",
472 "irq-info",
473 NULL
474};
475
476static struct {
477 u64 (*func)(void);
478 const char *name;
479} trace_clocks[] = {
480 { trace_clock_local, "local" },
481 { trace_clock_global, "global" },
482 { trace_clock_counter, "counter" },
483};
484
485int trace_clock_id;
486
487/*
488 * trace_parser_get_init - gets the buffer for trace parser
489 */
490int trace_parser_get_init(struct trace_parser *parser, int size)
491{
492 memset(parser, 0, sizeof(*parser));
493
494 parser->buffer = kmalloc(size, GFP_KERNEL);
495 if (!parser->buffer)
496 return 1;
497
498 parser->size = size;
499 return 0;
500}
501
502/*
503 * trace_parser_put - frees the buffer for trace parser
504 */
505void trace_parser_put(struct trace_parser *parser)
506{
507 kfree(parser->buffer);
508}
509
510/*
511 * trace_get_user - reads the user input string separated by space
512 * (matched by isspace(ch))
513 *
514 * For each string found the 'struct trace_parser' is updated,
515 * and the function returns.
516 *
517 * Returns number of bytes read.
518 *
519 * See kernel/trace/trace.h for 'struct trace_parser' details.
520 */
521int trace_get_user(struct trace_parser *parser, const char __user *ubuf,
522 size_t cnt, loff_t *ppos)
523{
524 char ch;
525 size_t read = 0;
526 ssize_t ret;
527
528 if (!*ppos)
529 trace_parser_clear(parser);
530
531 ret = get_user(ch, ubuf++);
532 if (ret)
533 goto out;
534
535 read++;
536 cnt--;
537
538 /*
539 * The parser is not finished with the last write,
540 * continue reading the user input without skipping spaces.
541 */
542 if (!parser->cont) {
543 /* skip white space */
544 while (cnt && isspace(ch)) {
545 ret = get_user(ch, ubuf++);
546 if (ret)
547 goto out;
548 read++;
549 cnt--;
550 }
551
552 /* only spaces were written */
553 if (isspace(ch)) {
554 *ppos += read;
555 ret = read;
556 goto out;
557 }
558
559 parser->idx = 0;
560 }
561
562 /* read the non-space input */
563 while (cnt && !isspace(ch)) {
564 if (parser->idx < parser->size - 1)
565 parser->buffer[parser->idx++] = ch;
566 else {
567 ret = -EINVAL;
568 goto out;
569 }
570 ret = get_user(ch, ubuf++);
571 if (ret)
572 goto out;
573 read++;
574 cnt--;
575 }
576
577 /* We either got finished input or we have to wait for another call. */
578 if (isspace(ch)) {
579 parser->buffer[parser->idx] = 0;
580 parser->cont = false;
581 } else {
582 parser->cont = true;
583 parser->buffer[parser->idx++] = ch;
584 }
585
586 *ppos += read;
587 ret = read;
588
589out:
590 return ret;
591}
592
593ssize_t trace_seq_to_user(struct trace_seq *s, char __user *ubuf, size_t cnt)
594{
595 int len;
596 int ret;
597
598 if (!cnt)
599 return 0;
600
601 if (s->len <= s->readpos)
602 return -EBUSY;
603
604 len = s->len - s->readpos;
605 if (cnt > len)
606 cnt = len;
607 ret = copy_to_user(ubuf, s->buffer + s->readpos, cnt);
608 if (ret == cnt)
609 return -EFAULT;
610
611 cnt -= ret;
612
613 s->readpos += cnt;
614 return cnt;
615}
616
617static ssize_t trace_seq_to_buffer(struct trace_seq *s, void *buf, size_t cnt)
618{
619 int len;
620
621 if (s->len <= s->readpos)
622 return -EBUSY;
623
624 len = s->len - s->readpos;
625 if (cnt > len)
626 cnt = len;
627 memcpy(buf, s->buffer + s->readpos, cnt);
628
629 s->readpos += cnt;
630 return cnt;
631}
632
633/*
634 * ftrace_max_lock is used to protect the swapping of buffers
635 * when taking a max snapshot. The buffers themselves are
636 * protected by per_cpu spinlocks. But the action of the swap
637 * needs its own lock.
638 *
639 * This is defined as a arch_spinlock_t in order to help
640 * with performance when lockdep debugging is enabled.
641 *
642 * It is also used in other places outside the update_max_tr
643 * so it needs to be defined outside of the
644 * CONFIG_TRACER_MAX_TRACE.
645 */
646static arch_spinlock_t ftrace_max_lock =
647 (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
648
649unsigned long __read_mostly tracing_thresh;
650
651#ifdef CONFIG_TRACER_MAX_TRACE
652unsigned long __read_mostly tracing_max_latency;
653
654/*
655 * Copy the new maximum trace into the separate maximum-trace
656 * structure. (this way the maximum trace is permanently saved,
657 * for later retrieval via /sys/kernel/debug/tracing/latency_trace)
658 */
659static void
660__update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
661{
662 struct trace_array_cpu *data = tr->data[cpu];
663 struct trace_array_cpu *max_data;
664
665 max_tr.cpu = cpu;
666 max_tr.time_start = data->preempt_timestamp;
667
668 max_data = max_tr.data[cpu];
669 max_data->saved_latency = tracing_max_latency;
670 max_data->critical_start = data->critical_start;
671 max_data->critical_end = data->critical_end;
672
673 memcpy(max_data->comm, tsk->comm, TASK_COMM_LEN);
674 max_data->pid = tsk->pid;
675 max_data->uid = task_uid(tsk);
676 max_data->nice = tsk->static_prio - 20 - MAX_RT_PRIO;
677 max_data->policy = tsk->policy;
678 max_data->rt_priority = tsk->rt_priority;
679
680 /* record this tasks comm */
681 tracing_record_cmdline(tsk);
682}
683
684/**
685 * update_max_tr - snapshot all trace buffers from global_trace to max_tr
686 * @tr: tracer
687 * @tsk: the task with the latency
688 * @cpu: The cpu that initiated the trace.
689 *
690 * Flip the buffers between the @tr and the max_tr and record information
691 * about which task was the cause of this latency.
692 */
693void
694update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
695{
696 struct ring_buffer *buf = tr->buffer;
697
698 if (trace_stop_count)
699 return;
700
701 WARN_ON_ONCE(!irqs_disabled());
702 if (!current_trace->use_max_tr) {
703 WARN_ON_ONCE(1);
704 return;
705 }
706 arch_spin_lock(&ftrace_max_lock);
707
708 tr->buffer = max_tr.buffer;
709 max_tr.buffer = buf;
710
711 __update_max_tr(tr, tsk, cpu);
712 arch_spin_unlock(&ftrace_max_lock);
713}
714
715/**
716 * update_max_tr_single - only copy one trace over, and reset the rest
717 * @tr - tracer
718 * @tsk - task with the latency
719 * @cpu - the cpu of the buffer to copy.
720 *
721 * Flip the trace of a single CPU buffer between the @tr and the max_tr.
722 */
723void
724update_max_tr_single(struct trace_array *tr, struct task_struct *tsk, int cpu)
725{
726 int ret;
727
728 if (trace_stop_count)
729 return;
730
731 WARN_ON_ONCE(!irqs_disabled());
732 if (!current_trace->use_max_tr) {
733 WARN_ON_ONCE(1);
734 return;
735 }
736
737 arch_spin_lock(&ftrace_max_lock);
738
739 ret = ring_buffer_swap_cpu(max_tr.buffer, tr->buffer, cpu);
740
741 if (ret == -EBUSY) {
742 /*
743 * We failed to swap the buffer due to a commit taking
744 * place on this CPU. We fail to record, but we reset
745 * the max trace buffer (no one writes directly to it)
746 * and flag that it failed.
747 */
748 trace_array_printk(&max_tr, _THIS_IP_,
749 "Failed to swap buffers due to commit in progress\n");
750 }
751
752 WARN_ON_ONCE(ret && ret != -EAGAIN && ret != -EBUSY);
753
754 __update_max_tr(tr, tsk, cpu);
755 arch_spin_unlock(&ftrace_max_lock);
756}
757#endif /* CONFIG_TRACER_MAX_TRACE */
758
759/**
760 * register_tracer - register a tracer with the ftrace system.
761 * @type - the plugin for the tracer
762 *
763 * Register a new plugin tracer.
764 */
765int register_tracer(struct tracer *type)
766{
767 struct tracer *t;
768 int ret = 0;
769
770 if (!type->name) {
771 pr_info("Tracer must have a name\n");
772 return -1;
773 }
774
775 if (strlen(type->name) >= MAX_TRACER_SIZE) {
776 pr_info("Tracer has a name longer than %d\n", MAX_TRACER_SIZE);
777 return -1;
778 }
779
780 mutex_lock(&trace_types_lock);
781
782 tracing_selftest_running = true;
783
784 for (t = trace_types; t; t = t->next) {
785 if (strcmp(type->name, t->name) == 0) {
786 /* already found */
787 pr_info("Tracer %s already registered\n",
788 type->name);
789 ret = -1;
790 goto out;
791 }
792 }
793
794 if (!type->set_flag)
795 type->set_flag = &dummy_set_flag;
796 if (!type->flags)
797 type->flags = &dummy_tracer_flags;
798 else
799 if (!type->flags->opts)
800 type->flags->opts = dummy_tracer_opt;
801 if (!type->wait_pipe)
802 type->wait_pipe = default_wait_pipe;
803
804
805#ifdef CONFIG_FTRACE_STARTUP_TEST
806 if (type->selftest && !tracing_selftest_disabled) {
807 struct tracer *saved_tracer = current_trace;
808 struct trace_array *tr = &global_trace;
809
810 /*
811 * Run a selftest on this tracer.
812 * Here we reset the trace buffer, and set the current
813 * tracer to be this tracer. The tracer can then run some
814 * internal tracing to verify that everything is in order.
815 * If we fail, we do not register this tracer.
816 */
817 tracing_reset_online_cpus(tr);
818
819 current_trace = type;
820
821 /* If we expanded the buffers, make sure the max is expanded too */
822 if (ring_buffer_expanded && type->use_max_tr)
823 ring_buffer_resize(max_tr.buffer, trace_buf_size,
824 RING_BUFFER_ALL_CPUS);
825
826 /* the test is responsible for initializing and enabling */
827 pr_info("Testing tracer %s: ", type->name);
828 ret = type->selftest(type, tr);
829 /* the test is responsible for resetting too */
830 current_trace = saved_tracer;
831 if (ret) {
832 printk(KERN_CONT "FAILED!\n");
833 goto out;
834 }
835 /* Only reset on passing, to avoid touching corrupted buffers */
836 tracing_reset_online_cpus(tr);
837
838 /* Shrink the max buffer again */
839 if (ring_buffer_expanded && type->use_max_tr)
840 ring_buffer_resize(max_tr.buffer, 1,
841 RING_BUFFER_ALL_CPUS);
842
843 printk(KERN_CONT "PASSED\n");
844 }
845#endif
846
847 type->next = trace_types;
848 trace_types = type;
849
850 out:
851 tracing_selftest_running = false;
852 mutex_unlock(&trace_types_lock);
853
854 if (ret || !default_bootup_tracer)
855 goto out_unlock;
856
857 if (strncmp(default_bootup_tracer, type->name, MAX_TRACER_SIZE))
858 goto out_unlock;
859
860 printk(KERN_INFO "Starting tracer '%s'\n", type->name);
861 /* Do we want this tracer to start on bootup? */
862 tracing_set_tracer(type->name);
863 default_bootup_tracer = NULL;
864 /* disable other selftests, since this will break it. */
865 tracing_selftest_disabled = 1;
866#ifdef CONFIG_FTRACE_STARTUP_TEST
867 printk(KERN_INFO "Disabling FTRACE selftests due to running tracer '%s'\n",
868 type->name);
869#endif
870
871 out_unlock:
872 return ret;
873}
874
875void unregister_tracer(struct tracer *type)
876{
877 struct tracer **t;
878
879 mutex_lock(&trace_types_lock);
880 for (t = &trace_types; *t; t = &(*t)->next) {
881 if (*t == type)
882 goto found;
883 }
884 pr_info("Tracer %s not registered\n", type->name);
885 goto out;
886
887 found:
888 *t = (*t)->next;
889
890 if (type == current_trace && tracer_enabled) {
891 tracer_enabled = 0;
892 tracing_stop();
893 if (current_trace->stop)
894 current_trace->stop(&global_trace);
895 current_trace = &nop_trace;
896 }
897out:
898 mutex_unlock(&trace_types_lock);
899}
900
901void tracing_reset(struct trace_array *tr, int cpu)
902{
903 struct ring_buffer *buffer = tr->buffer;
904
905 ring_buffer_record_disable(buffer);
906
907 /* Make sure all commits have finished */
908 synchronize_sched();
909 ring_buffer_reset_cpu(buffer, cpu);
910
911 ring_buffer_record_enable(buffer);
912}
913
914void tracing_reset_online_cpus(struct trace_array *tr)
915{
916 struct ring_buffer *buffer = tr->buffer;
917 int cpu;
918
919 ring_buffer_record_disable(buffer);
920
921 /* Make sure all commits have finished */
922 synchronize_sched();
923
924 tr->time_start = ftrace_now(tr->cpu);
925
926 for_each_online_cpu(cpu)
927 ring_buffer_reset_cpu(buffer, cpu);
928
929 ring_buffer_record_enable(buffer);
930}
931
932void tracing_reset_current(int cpu)
933{
934 tracing_reset(&global_trace, cpu);
935}
936
937void tracing_reset_current_online_cpus(void)
938{
939 tracing_reset_online_cpus(&global_trace);
940}
941
942#define SAVED_CMDLINES 128
943#define NO_CMDLINE_MAP UINT_MAX
944static unsigned map_pid_to_cmdline[PID_MAX_DEFAULT+1];
945static unsigned map_cmdline_to_pid[SAVED_CMDLINES];
946static char saved_cmdlines[SAVED_CMDLINES][TASK_COMM_LEN];
947static int cmdline_idx;
948static arch_spinlock_t trace_cmdline_lock = __ARCH_SPIN_LOCK_UNLOCKED;
949
950/* temporary disable recording */
951static atomic_t trace_record_cmdline_disabled __read_mostly;
952
953static void trace_init_cmdlines(void)
954{
955 memset(&map_pid_to_cmdline, NO_CMDLINE_MAP, sizeof(map_pid_to_cmdline));
956 memset(&map_cmdline_to_pid, NO_CMDLINE_MAP, sizeof(map_cmdline_to_pid));
957 cmdline_idx = 0;
958}
959
960int is_tracing_stopped(void)
961{
962 return trace_stop_count;
963}
964
965/**
966 * ftrace_off_permanent - disable all ftrace code permanently
967 *
968 * This should only be called when a serious anomally has
969 * been detected. This will turn off the function tracing,
970 * ring buffers, and other tracing utilites. It takes no
971 * locks and can be called from any context.
972 */
973void ftrace_off_permanent(void)
974{
975 tracing_disabled = 1;
976 ftrace_stop();
977 tracing_off_permanent();
978}
979
980/**
981 * tracing_start - quick start of the tracer
982 *
983 * If tracing is enabled but was stopped by tracing_stop,
984 * this will start the tracer back up.
985 */
986void tracing_start(void)
987{
988 struct ring_buffer *buffer;
989 unsigned long flags;
990
991 if (tracing_disabled)
992 return;
993
994 raw_spin_lock_irqsave(&tracing_start_lock, flags);
995 if (--trace_stop_count) {
996 if (trace_stop_count < 0) {
997 /* Someone screwed up their debugging */
998 WARN_ON_ONCE(1);
999 trace_stop_count = 0;
1000 }
1001 goto out;
1002 }
1003
1004 /* Prevent the buffers from switching */
1005 arch_spin_lock(&ftrace_max_lock);
1006
1007 buffer = global_trace.buffer;
1008 if (buffer)
1009 ring_buffer_record_enable(buffer);
1010
1011 buffer = max_tr.buffer;
1012 if (buffer)
1013 ring_buffer_record_enable(buffer);
1014
1015 arch_spin_unlock(&ftrace_max_lock);
1016
1017 ftrace_start();
1018 out:
1019 raw_spin_unlock_irqrestore(&tracing_start_lock, flags);
1020}
1021
1022/**
1023 * tracing_stop - quick stop of the tracer
1024 *
1025 * Light weight way to stop tracing. Use in conjunction with
1026 * tracing_start.
1027 */
1028void tracing_stop(void)
1029{
1030 struct ring_buffer *buffer;
1031 unsigned long flags;
1032
1033 ftrace_stop();
1034 raw_spin_lock_irqsave(&tracing_start_lock, flags);
1035 if (trace_stop_count++)
1036 goto out;
1037
1038 /* Prevent the buffers from switching */
1039 arch_spin_lock(&ftrace_max_lock);
1040
1041 buffer = global_trace.buffer;
1042 if (buffer)
1043 ring_buffer_record_disable(buffer);
1044
1045 buffer = max_tr.buffer;
1046 if (buffer)
1047 ring_buffer_record_disable(buffer);
1048
1049 arch_spin_unlock(&ftrace_max_lock);
1050
1051 out:
1052 raw_spin_unlock_irqrestore(&tracing_start_lock, flags);
1053}
1054
1055void trace_stop_cmdline_recording(void);
1056
1057static void trace_save_cmdline(struct task_struct *tsk)
1058{
1059 unsigned pid, idx;
1060
1061 if (!tsk->pid || unlikely(tsk->pid > PID_MAX_DEFAULT))
1062 return;
1063
1064 /*
1065 * It's not the end of the world if we don't get
1066 * the lock, but we also don't want to spin
1067 * nor do we want to disable interrupts,
1068 * so if we miss here, then better luck next time.
1069 */
1070 if (!arch_spin_trylock(&trace_cmdline_lock))
1071 return;
1072
1073 idx = map_pid_to_cmdline[tsk->pid];
1074 if (idx == NO_CMDLINE_MAP) {
1075 idx = (cmdline_idx + 1) % SAVED_CMDLINES;
1076
1077 /*
1078 * Check whether the cmdline buffer at idx has a pid
1079 * mapped. We are going to overwrite that entry so we
1080 * need to clear the map_pid_to_cmdline. Otherwise we
1081 * would read the new comm for the old pid.
1082 */
1083 pid = map_cmdline_to_pid[idx];
1084 if (pid != NO_CMDLINE_MAP)
1085 map_pid_to_cmdline[pid] = NO_CMDLINE_MAP;
1086
1087 map_cmdline_to_pid[idx] = tsk->pid;
1088 map_pid_to_cmdline[tsk->pid] = idx;
1089
1090 cmdline_idx = idx;
1091 }
1092
1093 memcpy(&saved_cmdlines[idx], tsk->comm, TASK_COMM_LEN);
1094
1095 arch_spin_unlock(&trace_cmdline_lock);
1096}
1097
1098void trace_find_cmdline(int pid, char comm[])
1099{
1100 unsigned map;
1101
1102 if (!pid) {
1103 strcpy(comm, "<idle>");
1104 return;
1105 }
1106
1107 if (WARN_ON_ONCE(pid < 0)) {
1108 strcpy(comm, "<XXX>");
1109 return;
1110 }
1111
1112 if (pid > PID_MAX_DEFAULT) {
1113 strcpy(comm, "<...>");
1114 return;
1115 }
1116
1117 preempt_disable();
1118 arch_spin_lock(&trace_cmdline_lock);
1119 map = map_pid_to_cmdline[pid];
1120 if (map != NO_CMDLINE_MAP)
1121 strcpy(comm, saved_cmdlines[map]);
1122 else
1123 strcpy(comm, "<...>");
1124
1125 arch_spin_unlock(&trace_cmdline_lock);
1126 preempt_enable();
1127}
1128
1129void tracing_record_cmdline(struct task_struct *tsk)
1130{
1131 if (atomic_read(&trace_record_cmdline_disabled) || !tracer_enabled ||
1132 !tracing_is_on())
1133 return;
1134
1135 trace_save_cmdline(tsk);
1136}
1137
1138void
1139tracing_generic_entry_update(struct trace_entry *entry, unsigned long flags,
1140 int pc)
1141{
1142 struct task_struct *tsk = current;
1143
1144 entry->preempt_count = pc & 0xff;
1145 entry->pid = (tsk) ? tsk->pid : 0;
1146 entry->padding = 0;
1147 entry->flags =
1148#ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT
1149 (irqs_disabled_flags(flags) ? TRACE_FLAG_IRQS_OFF : 0) |
1150#else
1151 TRACE_FLAG_IRQS_NOSUPPORT |
1152#endif
1153 ((pc & HARDIRQ_MASK) ? TRACE_FLAG_HARDIRQ : 0) |
1154 ((pc & SOFTIRQ_MASK) ? TRACE_FLAG_SOFTIRQ : 0) |
1155 (need_resched() ? TRACE_FLAG_NEED_RESCHED : 0);
1156}
1157EXPORT_SYMBOL_GPL(tracing_generic_entry_update);
1158
1159struct ring_buffer_event *
1160trace_buffer_lock_reserve(struct ring_buffer *buffer,
1161 int type,
1162 unsigned long len,
1163 unsigned long flags, int pc)
1164{
1165 struct ring_buffer_event *event;
1166
1167 event = ring_buffer_lock_reserve(buffer, len);
1168 if (event != NULL) {
1169 struct trace_entry *ent = ring_buffer_event_data(event);
1170
1171 tracing_generic_entry_update(ent, flags, pc);
1172 ent->type = type;
1173 }
1174
1175 return event;
1176}
1177
1178static inline void
1179__trace_buffer_unlock_commit(struct ring_buffer *buffer,
1180 struct ring_buffer_event *event,
1181 unsigned long flags, int pc,
1182 int wake)
1183{
1184 ring_buffer_unlock_commit(buffer, event);
1185
1186 ftrace_trace_stack(buffer, flags, 6, pc);
1187 ftrace_trace_userstack(buffer, flags, pc);
1188
1189 if (wake)
1190 trace_wake_up();
1191}
1192
1193void trace_buffer_unlock_commit(struct ring_buffer *buffer,
1194 struct ring_buffer_event *event,
1195 unsigned long flags, int pc)
1196{
1197 __trace_buffer_unlock_commit(buffer, event, flags, pc, 1);
1198}
1199
1200struct ring_buffer_event *
1201trace_current_buffer_lock_reserve(struct ring_buffer **current_rb,
1202 int type, unsigned long len,
1203 unsigned long flags, int pc)
1204{
1205 *current_rb = global_trace.buffer;
1206 return trace_buffer_lock_reserve(*current_rb,
1207 type, len, flags, pc);
1208}
1209EXPORT_SYMBOL_GPL(trace_current_buffer_lock_reserve);
1210
1211void trace_current_buffer_unlock_commit(struct ring_buffer *buffer,
1212 struct ring_buffer_event *event,
1213 unsigned long flags, int pc)
1214{
1215 __trace_buffer_unlock_commit(buffer, event, flags, pc, 1);
1216}
1217EXPORT_SYMBOL_GPL(trace_current_buffer_unlock_commit);
1218
1219void trace_nowake_buffer_unlock_commit(struct ring_buffer *buffer,
1220 struct ring_buffer_event *event,
1221 unsigned long flags, int pc)
1222{
1223 __trace_buffer_unlock_commit(buffer, event, flags, pc, 0);
1224}
1225EXPORT_SYMBOL_GPL(trace_nowake_buffer_unlock_commit);
1226
1227void trace_nowake_buffer_unlock_commit_regs(struct ring_buffer *buffer,
1228 struct ring_buffer_event *event,
1229 unsigned long flags, int pc,
1230 struct pt_regs *regs)
1231{
1232 ring_buffer_unlock_commit(buffer, event);
1233
1234 ftrace_trace_stack_regs(buffer, flags, 0, pc, regs);
1235 ftrace_trace_userstack(buffer, flags, pc);
1236}
1237EXPORT_SYMBOL_GPL(trace_nowake_buffer_unlock_commit_regs);
1238
1239void trace_current_buffer_discard_commit(struct ring_buffer *buffer,
1240 struct ring_buffer_event *event)
1241{
1242 ring_buffer_discard_commit(buffer, event);
1243}
1244EXPORT_SYMBOL_GPL(trace_current_buffer_discard_commit);
1245
1246void
1247trace_function(struct trace_array *tr,
1248 unsigned long ip, unsigned long parent_ip, unsigned long flags,
1249 int pc)
1250{
1251 struct ftrace_event_call *call = &event_function;
1252 struct ring_buffer *buffer = tr->buffer;
1253 struct ring_buffer_event *event;
1254 struct ftrace_entry *entry;
1255
1256 /* If we are reading the ring buffer, don't trace */
1257 if (unlikely(__this_cpu_read(ftrace_cpu_disabled)))
1258 return;
1259
1260 event = trace_buffer_lock_reserve(buffer, TRACE_FN, sizeof(*entry),
1261 flags, pc);
1262 if (!event)
1263 return;
1264 entry = ring_buffer_event_data(event);
1265 entry->ip = ip;
1266 entry->parent_ip = parent_ip;
1267
1268 if (!filter_check_discard(call, entry, buffer, event))
1269 ring_buffer_unlock_commit(buffer, event);
1270}
1271
1272void
1273ftrace(struct trace_array *tr, struct trace_array_cpu *data,
1274 unsigned long ip, unsigned long parent_ip, unsigned long flags,
1275 int pc)
1276{
1277 if (likely(!atomic_read(&data->disabled)))
1278 trace_function(tr, ip, parent_ip, flags, pc);
1279}
1280
1281#ifdef CONFIG_STACKTRACE
1282
1283#define FTRACE_STACK_MAX_ENTRIES (PAGE_SIZE / sizeof(unsigned long))
1284struct ftrace_stack {
1285 unsigned long calls[FTRACE_STACK_MAX_ENTRIES];
1286};
1287
1288static DEFINE_PER_CPU(struct ftrace_stack, ftrace_stack);
1289static DEFINE_PER_CPU(int, ftrace_stack_reserve);
1290
1291static void __ftrace_trace_stack(struct ring_buffer *buffer,
1292 unsigned long flags,
1293 int skip, int pc, struct pt_regs *regs)
1294{
1295 struct ftrace_event_call *call = &event_kernel_stack;
1296 struct ring_buffer_event *event;
1297 struct stack_entry *entry;
1298 struct stack_trace trace;
1299 int use_stack;
1300 int size = FTRACE_STACK_ENTRIES;
1301
1302 trace.nr_entries = 0;
1303 trace.skip = skip;
1304
1305 /*
1306 * Since events can happen in NMIs there's no safe way to
1307 * use the per cpu ftrace_stacks. We reserve it and if an interrupt
1308 * or NMI comes in, it will just have to use the default
1309 * FTRACE_STACK_SIZE.
1310 */
1311 preempt_disable_notrace();
1312
1313 use_stack = ++__get_cpu_var(ftrace_stack_reserve);
1314 /*
1315 * We don't need any atomic variables, just a barrier.
1316 * If an interrupt comes in, we don't care, because it would
1317 * have exited and put the counter back to what we want.
1318 * We just need a barrier to keep gcc from moving things
1319 * around.
1320 */
1321 barrier();
1322 if (use_stack == 1) {
1323 trace.entries = &__get_cpu_var(ftrace_stack).calls[0];
1324 trace.max_entries = FTRACE_STACK_MAX_ENTRIES;
1325
1326 if (regs)
1327 save_stack_trace_regs(regs, &trace);
1328 else
1329 save_stack_trace(&trace);
1330
1331 if (trace.nr_entries > size)
1332 size = trace.nr_entries;
1333 } else
1334 /* From now on, use_stack is a boolean */
1335 use_stack = 0;
1336
1337 size *= sizeof(unsigned long);
1338
1339 event = trace_buffer_lock_reserve(buffer, TRACE_STACK,
1340 sizeof(*entry) + size, flags, pc);
1341 if (!event)
1342 goto out;
1343 entry = ring_buffer_event_data(event);
1344
1345 memset(&entry->caller, 0, size);
1346
1347 if (use_stack)
1348 memcpy(&entry->caller, trace.entries,
1349 trace.nr_entries * sizeof(unsigned long));
1350 else {
1351 trace.max_entries = FTRACE_STACK_ENTRIES;
1352 trace.entries = entry->caller;
1353 if (regs)
1354 save_stack_trace_regs(regs, &trace);
1355 else
1356 save_stack_trace(&trace);
1357 }
1358
1359 entry->size = trace.nr_entries;
1360
1361 if (!filter_check_discard(call, entry, buffer, event))
1362 ring_buffer_unlock_commit(buffer, event);
1363
1364 out:
1365 /* Again, don't let gcc optimize things here */
1366 barrier();
1367 __get_cpu_var(ftrace_stack_reserve)--;
1368 preempt_enable_notrace();
1369
1370}
1371
1372void ftrace_trace_stack_regs(struct ring_buffer *buffer, unsigned long flags,
1373 int skip, int pc, struct pt_regs *regs)
1374{
1375 if (!(trace_flags & TRACE_ITER_STACKTRACE))
1376 return;
1377
1378 __ftrace_trace_stack(buffer, flags, skip, pc, regs);
1379}
1380
1381void ftrace_trace_stack(struct ring_buffer *buffer, unsigned long flags,
1382 int skip, int pc)
1383{
1384 if (!(trace_flags & TRACE_ITER_STACKTRACE))
1385 return;
1386
1387 __ftrace_trace_stack(buffer, flags, skip, pc, NULL);
1388}
1389
1390void __trace_stack(struct trace_array *tr, unsigned long flags, int skip,
1391 int pc)
1392{
1393 __ftrace_trace_stack(tr->buffer, flags, skip, pc, NULL);
1394}
1395
1396/**
1397 * trace_dump_stack - record a stack back trace in the trace buffer
1398 */
1399void trace_dump_stack(void)
1400{
1401 unsigned long flags;
1402
1403 if (tracing_disabled || tracing_selftest_running)
1404 return;
1405
1406 local_save_flags(flags);
1407
1408 /* skipping 3 traces, seems to get us at the caller of this function */
1409 __ftrace_trace_stack(global_trace.buffer, flags, 3, preempt_count(), NULL);
1410}
1411
1412static DEFINE_PER_CPU(int, user_stack_count);
1413
1414void
1415ftrace_trace_userstack(struct ring_buffer *buffer, unsigned long flags, int pc)
1416{
1417 struct ftrace_event_call *call = &event_user_stack;
1418 struct ring_buffer_event *event;
1419 struct userstack_entry *entry;
1420 struct stack_trace trace;
1421
1422 if (!(trace_flags & TRACE_ITER_USERSTACKTRACE))
1423 return;
1424
1425 /*
1426 * NMIs can not handle page faults, even with fix ups.
1427 * The save user stack can (and often does) fault.
1428 */
1429 if (unlikely(in_nmi()))
1430 return;
1431
1432 /*
1433 * prevent recursion, since the user stack tracing may
1434 * trigger other kernel events.
1435 */
1436 preempt_disable();
1437 if (__this_cpu_read(user_stack_count))
1438 goto out;
1439
1440 __this_cpu_inc(user_stack_count);
1441
1442 event = trace_buffer_lock_reserve(buffer, TRACE_USER_STACK,
1443 sizeof(*entry), flags, pc);
1444 if (!event)
1445 goto out_drop_count;
1446 entry = ring_buffer_event_data(event);
1447
1448 entry->tgid = current->tgid;
1449 memset(&entry->caller, 0, sizeof(entry->caller));
1450
1451 trace.nr_entries = 0;
1452 trace.max_entries = FTRACE_STACK_ENTRIES;
1453 trace.skip = 0;
1454 trace.entries = entry->caller;
1455
1456 save_stack_trace_user(&trace);
1457 if (!filter_check_discard(call, entry, buffer, event))
1458 ring_buffer_unlock_commit(buffer, event);
1459
1460 out_drop_count:
1461 __this_cpu_dec(user_stack_count);
1462 out:
1463 preempt_enable();
1464}
1465
1466#ifdef UNUSED
1467static void __trace_userstack(struct trace_array *tr, unsigned long flags)
1468{
1469 ftrace_trace_userstack(tr, flags, preempt_count());
1470}
1471#endif /* UNUSED */
1472
1473#endif /* CONFIG_STACKTRACE */
1474
1475/* created for use with alloc_percpu */
1476struct trace_buffer_struct {
1477 char buffer[TRACE_BUF_SIZE];
1478};
1479
1480static struct trace_buffer_struct *trace_percpu_buffer;
1481static struct trace_buffer_struct *trace_percpu_sirq_buffer;
1482static struct trace_buffer_struct *trace_percpu_irq_buffer;
1483static struct trace_buffer_struct *trace_percpu_nmi_buffer;
1484
1485/*
1486 * The buffer used is dependent on the context. There is a per cpu
1487 * buffer for normal context, softirq contex, hard irq context and
1488 * for NMI context. Thise allows for lockless recording.
1489 *
1490 * Note, if the buffers failed to be allocated, then this returns NULL
1491 */
1492static char *get_trace_buf(void)
1493{
1494 struct trace_buffer_struct *percpu_buffer;
1495 struct trace_buffer_struct *buffer;
1496
1497 /*
1498 * If we have allocated per cpu buffers, then we do not
1499 * need to do any locking.
1500 */
1501 if (in_nmi())
1502 percpu_buffer = trace_percpu_nmi_buffer;
1503 else if (in_irq())
1504 percpu_buffer = trace_percpu_irq_buffer;
1505 else if (in_softirq())
1506 percpu_buffer = trace_percpu_sirq_buffer;
1507 else
1508 percpu_buffer = trace_percpu_buffer;
1509
1510 if (!percpu_buffer)
1511 return NULL;
1512
1513 buffer = per_cpu_ptr(percpu_buffer, smp_processor_id());
1514
1515 return buffer->buffer;
1516}
1517
1518static int alloc_percpu_trace_buffer(void)
1519{
1520 struct trace_buffer_struct *buffers;
1521 struct trace_buffer_struct *sirq_buffers;
1522 struct trace_buffer_struct *irq_buffers;
1523 struct trace_buffer_struct *nmi_buffers;
1524
1525 buffers = alloc_percpu(struct trace_buffer_struct);
1526 if (!buffers)
1527 goto err_warn;
1528
1529 sirq_buffers = alloc_percpu(struct trace_buffer_struct);
1530 if (!sirq_buffers)
1531 goto err_sirq;
1532
1533 irq_buffers = alloc_percpu(struct trace_buffer_struct);
1534 if (!irq_buffers)
1535 goto err_irq;
1536
1537 nmi_buffers = alloc_percpu(struct trace_buffer_struct);
1538 if (!nmi_buffers)
1539 goto err_nmi;
1540
1541 trace_percpu_buffer = buffers;
1542 trace_percpu_sirq_buffer = sirq_buffers;
1543 trace_percpu_irq_buffer = irq_buffers;
1544 trace_percpu_nmi_buffer = nmi_buffers;
1545
1546 return 0;
1547
1548 err_nmi:
1549 free_percpu(irq_buffers);
1550 err_irq:
1551 free_percpu(sirq_buffers);
1552 err_sirq:
1553 free_percpu(buffers);
1554 err_warn:
1555 WARN(1, "Could not allocate percpu trace_printk buffer");
1556 return -ENOMEM;
1557}
1558
1559void trace_printk_init_buffers(void)
1560{
1561 static int buffers_allocated;
1562
1563 if (buffers_allocated)
1564 return;
1565
1566 if (alloc_percpu_trace_buffer())
1567 return;
1568
1569 pr_info("ftrace: Allocated trace_printk buffers\n");
1570
1571 buffers_allocated = 1;
1572}
1573
1574/**
1575 * trace_vbprintk - write binary msg to tracing buffer
1576 *
1577 */
1578int trace_vbprintk(unsigned long ip, const char *fmt, va_list args)
1579{
1580 struct ftrace_event_call *call = &event_bprint;
1581 struct ring_buffer_event *event;
1582 struct ring_buffer *buffer;
1583 struct trace_array *tr = &global_trace;
1584 struct bprint_entry *entry;
1585 unsigned long flags;
1586 char *tbuffer;
1587 int len = 0, size, pc;
1588
1589 if (unlikely(tracing_selftest_running || tracing_disabled))
1590 return 0;
1591
1592 /* Don't pollute graph traces with trace_vprintk internals */
1593 pause_graph_tracing();
1594
1595 pc = preempt_count();
1596 preempt_disable_notrace();
1597
1598 tbuffer = get_trace_buf();
1599 if (!tbuffer) {
1600 len = 0;
1601 goto out;
1602 }
1603
1604 len = vbin_printf((u32 *)tbuffer, TRACE_BUF_SIZE/sizeof(int), fmt, args);
1605
1606 if (len > TRACE_BUF_SIZE/sizeof(int) || len < 0)
1607 goto out;
1608
1609 local_save_flags(flags);
1610 size = sizeof(*entry) + sizeof(u32) * len;
1611 buffer = tr->buffer;
1612 event = trace_buffer_lock_reserve(buffer, TRACE_BPRINT, size,
1613 flags, pc);
1614 if (!event)
1615 goto out;
1616 entry = ring_buffer_event_data(event);
1617 entry->ip = ip;
1618 entry->fmt = fmt;
1619
1620 memcpy(entry->buf, tbuffer, sizeof(u32) * len);
1621 if (!filter_check_discard(call, entry, buffer, event)) {
1622 ring_buffer_unlock_commit(buffer, event);
1623 ftrace_trace_stack(buffer, flags, 6, pc);
1624 }
1625
1626out:
1627 preempt_enable_notrace();
1628 unpause_graph_tracing();
1629
1630 return len;
1631}
1632EXPORT_SYMBOL_GPL(trace_vbprintk);
1633
1634int trace_array_printk(struct trace_array *tr,
1635 unsigned long ip, const char *fmt, ...)
1636{
1637 int ret;
1638 va_list ap;
1639
1640 if (!(trace_flags & TRACE_ITER_PRINTK))
1641 return 0;
1642
1643 va_start(ap, fmt);
1644 ret = trace_array_vprintk(tr, ip, fmt, ap);
1645 va_end(ap);
1646 return ret;
1647}
1648
1649int trace_array_vprintk(struct trace_array *tr,
1650 unsigned long ip, const char *fmt, va_list args)
1651{
1652 struct ftrace_event_call *call = &event_print;
1653 struct ring_buffer_event *event;
1654 struct ring_buffer *buffer;
1655 int len = 0, size, pc;
1656 struct print_entry *entry;
1657 unsigned long flags;
1658 char *tbuffer;
1659
1660 if (tracing_disabled || tracing_selftest_running)
1661 return 0;
1662
1663 /* Don't pollute graph traces with trace_vprintk internals */
1664 pause_graph_tracing();
1665
1666 pc = preempt_count();
1667 preempt_disable_notrace();
1668
1669
1670 tbuffer = get_trace_buf();
1671 if (!tbuffer) {
1672 len = 0;
1673 goto out;
1674 }
1675
1676 len = vsnprintf(tbuffer, TRACE_BUF_SIZE, fmt, args);
1677 if (len > TRACE_BUF_SIZE)
1678 goto out;
1679
1680 local_save_flags(flags);
1681 size = sizeof(*entry) + len + 1;
1682 buffer = tr->buffer;
1683 event = trace_buffer_lock_reserve(buffer, TRACE_PRINT, size,
1684 flags, pc);
1685 if (!event)
1686 goto out;
1687 entry = ring_buffer_event_data(event);
1688 entry->ip = ip;
1689
1690 memcpy(&entry->buf, tbuffer, len);
1691 entry->buf[len] = '\0';
1692 if (!filter_check_discard(call, entry, buffer, event)) {
1693 ring_buffer_unlock_commit(buffer, event);
1694 ftrace_trace_stack(buffer, flags, 6, pc);
1695 }
1696 out:
1697 preempt_enable_notrace();
1698 unpause_graph_tracing();
1699
1700 return len;
1701}
1702
1703int trace_vprintk(unsigned long ip, const char *fmt, va_list args)
1704{
1705 return trace_array_vprintk(&global_trace, ip, fmt, args);
1706}
1707EXPORT_SYMBOL_GPL(trace_vprintk);
1708
1709static void trace_iterator_increment(struct trace_iterator *iter)
1710{
1711 iter->idx++;
1712 if (iter->buffer_iter[iter->cpu])
1713 ring_buffer_read(iter->buffer_iter[iter->cpu], NULL);
1714}
1715
1716static struct trace_entry *
1717peek_next_entry(struct trace_iterator *iter, int cpu, u64 *ts,
1718 unsigned long *lost_events)
1719{
1720 struct ring_buffer_event *event;
1721 struct ring_buffer_iter *buf_iter = iter->buffer_iter[cpu];
1722
1723 if (buf_iter)
1724 event = ring_buffer_iter_peek(buf_iter, ts);
1725 else
1726 event = ring_buffer_peek(iter->tr->buffer, cpu, ts,
1727 lost_events);
1728
1729 if (event) {
1730 iter->ent_size = ring_buffer_event_length(event);
1731 return ring_buffer_event_data(event);
1732 }
1733 iter->ent_size = 0;
1734 return NULL;
1735}
1736
1737static struct trace_entry *
1738__find_next_entry(struct trace_iterator *iter, int *ent_cpu,
1739 unsigned long *missing_events, u64 *ent_ts)
1740{
1741 struct ring_buffer *buffer = iter->tr->buffer;
1742 struct trace_entry *ent, *next = NULL;
1743 unsigned long lost_events = 0, next_lost = 0;
1744 int cpu_file = iter->cpu_file;
1745 u64 next_ts = 0, ts;
1746 int next_cpu = -1;
1747 int next_size = 0;
1748 int cpu;
1749
1750 /*
1751 * If we are in a per_cpu trace file, don't bother by iterating over
1752 * all cpu and peek directly.
1753 */
1754 if (cpu_file > TRACE_PIPE_ALL_CPU) {
1755 if (ring_buffer_empty_cpu(buffer, cpu_file))
1756 return NULL;
1757 ent = peek_next_entry(iter, cpu_file, ent_ts, missing_events);
1758 if (ent_cpu)
1759 *ent_cpu = cpu_file;
1760
1761 return ent;
1762 }
1763
1764 for_each_tracing_cpu(cpu) {
1765
1766 if (ring_buffer_empty_cpu(buffer, cpu))
1767 continue;
1768
1769 ent = peek_next_entry(iter, cpu, &ts, &lost_events);
1770
1771 /*
1772 * Pick the entry with the smallest timestamp:
1773 */
1774 if (ent && (!next || ts < next_ts)) {
1775 next = ent;
1776 next_cpu = cpu;
1777 next_ts = ts;
1778 next_lost = lost_events;
1779 next_size = iter->ent_size;
1780 }
1781 }
1782
1783 iter->ent_size = next_size;
1784
1785 if (ent_cpu)
1786 *ent_cpu = next_cpu;
1787
1788 if (ent_ts)
1789 *ent_ts = next_ts;
1790
1791 if (missing_events)
1792 *missing_events = next_lost;
1793
1794 return next;
1795}
1796
1797/* Find the next real entry, without updating the iterator itself */
1798struct trace_entry *trace_find_next_entry(struct trace_iterator *iter,
1799 int *ent_cpu, u64 *ent_ts)
1800{
1801 return __find_next_entry(iter, ent_cpu, NULL, ent_ts);
1802}
1803
1804/* Find the next real entry, and increment the iterator to the next entry */
1805void *trace_find_next_entry_inc(struct trace_iterator *iter)
1806{
1807 iter->ent = __find_next_entry(iter, &iter->cpu,
1808 &iter->lost_events, &iter->ts);
1809
1810 if (iter->ent)
1811 trace_iterator_increment(iter);
1812
1813 return iter->ent ? iter : NULL;
1814}
1815
1816static void trace_consume(struct trace_iterator *iter)
1817{
1818 ring_buffer_consume(iter->tr->buffer, iter->cpu, &iter->ts,
1819 &iter->lost_events);
1820}
1821
1822static void *s_next(struct seq_file *m, void *v, loff_t *pos)
1823{
1824 struct trace_iterator *iter = m->private;
1825 int i = (int)*pos;
1826 void *ent;
1827
1828 WARN_ON_ONCE(iter->leftover);
1829
1830 (*pos)++;
1831
1832 /* can't go backwards */
1833 if (iter->idx > i)
1834 return NULL;
1835
1836 if (iter->idx < 0)
1837 ent = trace_find_next_entry_inc(iter);
1838 else
1839 ent = iter;
1840
1841 while (ent && iter->idx < i)
1842 ent = trace_find_next_entry_inc(iter);
1843
1844 iter->pos = *pos;
1845
1846 return ent;
1847}
1848
1849void tracing_iter_reset(struct trace_iterator *iter, int cpu)
1850{
1851 struct trace_array *tr = iter->tr;
1852 struct ring_buffer_event *event;
1853 struct ring_buffer_iter *buf_iter;
1854 unsigned long entries = 0;
1855 u64 ts;
1856
1857 tr->data[cpu]->skipped_entries = 0;
1858
1859 if (!iter->buffer_iter[cpu])
1860 return;
1861
1862 buf_iter = iter->buffer_iter[cpu];
1863 ring_buffer_iter_reset(buf_iter);
1864
1865 /*
1866 * We could have the case with the max latency tracers
1867 * that a reset never took place on a cpu. This is evident
1868 * by the timestamp being before the start of the buffer.
1869 */
1870 while ((event = ring_buffer_iter_peek(buf_iter, &ts))) {
1871 if (ts >= iter->tr->time_start)
1872 break;
1873 entries++;
1874 ring_buffer_read(buf_iter, NULL);
1875 }
1876
1877 tr->data[cpu]->skipped_entries = entries;
1878}
1879
1880/*
1881 * The current tracer is copied to avoid a global locking
1882 * all around.
1883 */
1884static void *s_start(struct seq_file *m, loff_t *pos)
1885{
1886 struct trace_iterator *iter = m->private;
1887 static struct tracer *old_tracer;
1888 int cpu_file = iter->cpu_file;
1889 void *p = NULL;
1890 loff_t l = 0;
1891 int cpu;
1892
1893 /* copy the tracer to avoid using a global lock all around */
1894 mutex_lock(&trace_types_lock);
1895 if (unlikely(old_tracer != current_trace && current_trace)) {
1896 old_tracer = current_trace;
1897 *iter->trace = *current_trace;
1898 }
1899 mutex_unlock(&trace_types_lock);
1900
1901 atomic_inc(&trace_record_cmdline_disabled);
1902
1903 if (*pos != iter->pos) {
1904 iter->ent = NULL;
1905 iter->cpu = 0;
1906 iter->idx = -1;
1907
1908 if (cpu_file == TRACE_PIPE_ALL_CPU) {
1909 for_each_tracing_cpu(cpu)
1910 tracing_iter_reset(iter, cpu);
1911 } else
1912 tracing_iter_reset(iter, cpu_file);
1913
1914 iter->leftover = 0;
1915 for (p = iter; p && l < *pos; p = s_next(m, p, &l))
1916 ;
1917
1918 } else {
1919 /*
1920 * If we overflowed the seq_file before, then we want
1921 * to just reuse the trace_seq buffer again.
1922 */
1923 if (iter->leftover)
1924 p = iter;
1925 else {
1926 l = *pos - 1;
1927 p = s_next(m, p, &l);
1928 }
1929 }
1930
1931 trace_event_read_lock();
1932 trace_access_lock(cpu_file);
1933 return p;
1934}
1935
1936static void s_stop(struct seq_file *m, void *p)
1937{
1938 struct trace_iterator *iter = m->private;
1939
1940 atomic_dec(&trace_record_cmdline_disabled);
1941 trace_access_unlock(iter->cpu_file);
1942 trace_event_read_unlock();
1943}
1944
1945static void
1946get_total_entries(struct trace_array *tr, unsigned long *total, unsigned long *entries)
1947{
1948 unsigned long count;
1949 int cpu;
1950
1951 *total = 0;
1952 *entries = 0;
1953
1954 for_each_tracing_cpu(cpu) {
1955 count = ring_buffer_entries_cpu(tr->buffer, cpu);
1956 /*
1957 * If this buffer has skipped entries, then we hold all
1958 * entries for the trace and we need to ignore the
1959 * ones before the time stamp.
1960 */
1961 if (tr->data[cpu]->skipped_entries) {
1962 count -= tr->data[cpu]->skipped_entries;
1963 /* total is the same as the entries */
1964 *total += count;
1965 } else
1966 *total += count +
1967 ring_buffer_overrun_cpu(tr->buffer, cpu);
1968 *entries += count;
1969 }
1970}
1971
1972static void print_lat_help_header(struct seq_file *m)
1973{
1974 seq_puts(m, "# _------=> CPU# \n");
1975 seq_puts(m, "# / _-----=> irqs-off \n");
1976 seq_puts(m, "# | / _----=> need-resched \n");
1977 seq_puts(m, "# || / _---=> hardirq/softirq \n");
1978 seq_puts(m, "# ||| / _--=> preempt-depth \n");
1979 seq_puts(m, "# |||| / delay \n");
1980 seq_puts(m, "# cmd pid ||||| time | caller \n");
1981 seq_puts(m, "# \\ / ||||| \\ | / \n");
1982}
1983
1984static void print_event_info(struct trace_array *tr, struct seq_file *m)
1985{
1986 unsigned long total;
1987 unsigned long entries;
1988
1989 get_total_entries(tr, &total, &entries);
1990 seq_printf(m, "# entries-in-buffer/entries-written: %lu/%lu #P:%d\n",
1991 entries, total, num_online_cpus());
1992 seq_puts(m, "#\n");
1993}
1994
1995static void print_func_help_header(struct trace_array *tr, struct seq_file *m)
1996{
1997 print_event_info(tr, m);
1998 seq_puts(m, "# TASK-PID CPU# TIMESTAMP FUNCTION\n");
1999 seq_puts(m, "# | | | | |\n");
2000}
2001
2002static void print_func_help_header_irq(struct trace_array *tr, struct seq_file *m)
2003{
2004 print_event_info(tr, m);
2005 seq_puts(m, "# _-----=> irqs-off\n");
2006 seq_puts(m, "# / _----=> need-resched\n");
2007 seq_puts(m, "# | / _---=> hardirq/softirq\n");
2008 seq_puts(m, "# || / _--=> preempt-depth\n");
2009 seq_puts(m, "# ||| / delay\n");
2010 seq_puts(m, "# TASK-PID CPU# |||| TIMESTAMP FUNCTION\n");
2011 seq_puts(m, "# | | | |||| | |\n");
2012}
2013
2014void
2015print_trace_header(struct seq_file *m, struct trace_iterator *iter)
2016{
2017 unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
2018 struct trace_array *tr = iter->tr;
2019 struct trace_array_cpu *data = tr->data[tr->cpu];
2020 struct tracer *type = current_trace;
2021 unsigned long entries;
2022 unsigned long total;
2023 const char *name = "preemption";
2024
2025 if (type)
2026 name = type->name;
2027
2028 get_total_entries(tr, &total, &entries);
2029
2030 seq_printf(m, "# %s latency trace v1.1.5 on %s\n",
2031 name, UTS_RELEASE);
2032 seq_puts(m, "# -----------------------------------"
2033 "---------------------------------\n");
2034 seq_printf(m, "# latency: %lu us, #%lu/%lu, CPU#%d |"
2035 " (M:%s VP:%d, KP:%d, SP:%d HP:%d",
2036 nsecs_to_usecs(data->saved_latency),
2037 entries,
2038 total,
2039 tr->cpu,
2040#if defined(CONFIG_PREEMPT_NONE)
2041 "server",
2042#elif defined(CONFIG_PREEMPT_VOLUNTARY)
2043 "desktop",
2044#elif defined(CONFIG_PREEMPT)
2045 "preempt",
2046#else
2047 "unknown",
2048#endif
2049 /* These are reserved for later use */
2050 0, 0, 0, 0);
2051#ifdef CONFIG_SMP
2052 seq_printf(m, " #P:%d)\n", num_online_cpus());
2053#else
2054 seq_puts(m, ")\n");
2055#endif
2056 seq_puts(m, "# -----------------\n");
2057 seq_printf(m, "# | task: %.16s-%d "
2058 "(uid:%d nice:%ld policy:%ld rt_prio:%ld)\n",
2059 data->comm, data->pid, data->uid, data->nice,
2060 data->policy, data->rt_priority);
2061 seq_puts(m, "# -----------------\n");
2062
2063 if (data->critical_start) {
2064 seq_puts(m, "# => started at: ");
2065 seq_print_ip_sym(&iter->seq, data->critical_start, sym_flags);
2066 trace_print_seq(m, &iter->seq);
2067 seq_puts(m, "\n# => ended at: ");
2068 seq_print_ip_sym(&iter->seq, data->critical_end, sym_flags);
2069 trace_print_seq(m, &iter->seq);
2070 seq_puts(m, "\n#\n");
2071 }
2072
2073 seq_puts(m, "#\n");
2074}
2075
2076static void test_cpu_buff_start(struct trace_iterator *iter)
2077{
2078 struct trace_seq *s = &iter->seq;
2079
2080 if (!(trace_flags & TRACE_ITER_ANNOTATE))
2081 return;
2082
2083 if (!(iter->iter_flags & TRACE_FILE_ANNOTATE))
2084 return;
2085
2086 if (cpumask_test_cpu(iter->cpu, iter->started))
2087 return;
2088
2089 if (iter->tr->data[iter->cpu]->skipped_entries)
2090 return;
2091
2092 cpumask_set_cpu(iter->cpu, iter->started);
2093
2094 /* Don't print started cpu buffer for the first entry of the trace */
2095 if (iter->idx > 1)
2096 trace_seq_printf(s, "##### CPU %u buffer started ####\n",
2097 iter->cpu);
2098}
2099
2100static enum print_line_t print_trace_fmt(struct trace_iterator *iter)
2101{
2102 struct trace_seq *s = &iter->seq;
2103 unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
2104 struct trace_entry *entry;
2105 struct trace_event *event;
2106
2107 entry = iter->ent;
2108
2109 test_cpu_buff_start(iter);
2110
2111 event = ftrace_find_event(entry->type);
2112
2113 if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
2114 if (iter->iter_flags & TRACE_FILE_LAT_FMT) {
2115 if (!trace_print_lat_context(iter))
2116 goto partial;
2117 } else {
2118 if (!trace_print_context(iter))
2119 goto partial;
2120 }
2121 }
2122
2123 if (event)
2124 return event->funcs->trace(iter, sym_flags, event);
2125
2126 if (!trace_seq_printf(s, "Unknown type %d\n", entry->type))
2127 goto partial;
2128
2129 return TRACE_TYPE_HANDLED;
2130partial:
2131 return TRACE_TYPE_PARTIAL_LINE;
2132}
2133
2134static enum print_line_t print_raw_fmt(struct trace_iterator *iter)
2135{
2136 struct trace_seq *s = &iter->seq;
2137 struct trace_entry *entry;
2138 struct trace_event *event;
2139
2140 entry = iter->ent;
2141
2142 if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
2143 if (!trace_seq_printf(s, "%d %d %llu ",
2144 entry->pid, iter->cpu, iter->ts))
2145 goto partial;
2146 }
2147
2148 event = ftrace_find_event(entry->type);
2149 if (event)
2150 return event->funcs->raw(iter, 0, event);
2151
2152 if (!trace_seq_printf(s, "%d ?\n", entry->type))
2153 goto partial;
2154
2155 return TRACE_TYPE_HANDLED;
2156partial:
2157 return TRACE_TYPE_PARTIAL_LINE;
2158}
2159
2160static enum print_line_t print_hex_fmt(struct trace_iterator *iter)
2161{
2162 struct trace_seq *s = &iter->seq;
2163 unsigned char newline = '\n';
2164 struct trace_entry *entry;
2165 struct trace_event *event;
2166
2167 entry = iter->ent;
2168
2169 if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
2170 SEQ_PUT_HEX_FIELD_RET(s, entry->pid);
2171 SEQ_PUT_HEX_FIELD_RET(s, iter->cpu);
2172 SEQ_PUT_HEX_FIELD_RET(s, iter->ts);
2173 }
2174
2175 event = ftrace_find_event(entry->type);
2176 if (event) {
2177 enum print_line_t ret = event->funcs->hex(iter, 0, event);
2178 if (ret != TRACE_TYPE_HANDLED)
2179 return ret;
2180 }
2181
2182 SEQ_PUT_FIELD_RET(s, newline);
2183
2184 return TRACE_TYPE_HANDLED;
2185}
2186
2187static enum print_line_t print_bin_fmt(struct trace_iterator *iter)
2188{
2189 struct trace_seq *s = &iter->seq;
2190 struct trace_entry *entry;
2191 struct trace_event *event;
2192
2193 entry = iter->ent;
2194
2195 if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
2196 SEQ_PUT_FIELD_RET(s, entry->pid);
2197 SEQ_PUT_FIELD_RET(s, iter->cpu);
2198 SEQ_PUT_FIELD_RET(s, iter->ts);
2199 }
2200
2201 event = ftrace_find_event(entry->type);
2202 return event ? event->funcs->binary(iter, 0, event) :
2203 TRACE_TYPE_HANDLED;
2204}
2205
2206int trace_empty(struct trace_iterator *iter)
2207{
2208 int cpu;
2209
2210 /* If we are looking at one CPU buffer, only check that one */
2211 if (iter->cpu_file != TRACE_PIPE_ALL_CPU) {
2212 cpu = iter->cpu_file;
2213 if (iter->buffer_iter[cpu]) {
2214 if (!ring_buffer_iter_empty(iter->buffer_iter[cpu]))
2215 return 0;
2216 } else {
2217 if (!ring_buffer_empty_cpu(iter->tr->buffer, cpu))
2218 return 0;
2219 }
2220 return 1;
2221 }
2222
2223 for_each_tracing_cpu(cpu) {
2224 if (iter->buffer_iter[cpu]) {
2225 if (!ring_buffer_iter_empty(iter->buffer_iter[cpu]))
2226 return 0;
2227 } else {
2228 if (!ring_buffer_empty_cpu(iter->tr->buffer, cpu))
2229 return 0;
2230 }
2231 }
2232
2233 return 1;
2234}
2235
2236/* Called with trace_event_read_lock() held. */
2237enum print_line_t print_trace_line(struct trace_iterator *iter)
2238{
2239 enum print_line_t ret;
2240
2241 if (iter->lost_events &&
2242 !trace_seq_printf(&iter->seq, "CPU:%d [LOST %lu EVENTS]\n",
2243 iter->cpu, iter->lost_events))
2244 return TRACE_TYPE_PARTIAL_LINE;
2245
2246 if (iter->trace && iter->trace->print_line) {
2247 ret = iter->trace->print_line(iter);
2248 if (ret != TRACE_TYPE_UNHANDLED)
2249 return ret;
2250 }
2251
2252 if (iter->ent->type == TRACE_BPRINT &&
2253 trace_flags & TRACE_ITER_PRINTK &&
2254 trace_flags & TRACE_ITER_PRINTK_MSGONLY)
2255 return trace_print_bprintk_msg_only(iter);
2256
2257 if (iter->ent->type == TRACE_PRINT &&
2258 trace_flags & TRACE_ITER_PRINTK &&
2259 trace_flags & TRACE_ITER_PRINTK_MSGONLY)
2260 return trace_print_printk_msg_only(iter);
2261
2262 if (trace_flags & TRACE_ITER_BIN)
2263 return print_bin_fmt(iter);
2264
2265 if (trace_flags & TRACE_ITER_HEX)
2266 return print_hex_fmt(iter);
2267
2268 if (trace_flags & TRACE_ITER_RAW)
2269 return print_raw_fmt(iter);
2270
2271 return print_trace_fmt(iter);
2272}
2273
2274void trace_latency_header(struct seq_file *m)
2275{
2276 struct trace_iterator *iter = m->private;
2277
2278 /* print nothing if the buffers are empty */
2279 if (trace_empty(iter))
2280 return;
2281
2282 if (iter->iter_flags & TRACE_FILE_LAT_FMT)
2283 print_trace_header(m, iter);
2284
2285 if (!(trace_flags & TRACE_ITER_VERBOSE))
2286 print_lat_help_header(m);
2287}
2288
2289void trace_default_header(struct seq_file *m)
2290{
2291 struct trace_iterator *iter = m->private;
2292
2293 if (!(trace_flags & TRACE_ITER_CONTEXT_INFO))
2294 return;
2295
2296 if (iter->iter_flags & TRACE_FILE_LAT_FMT) {
2297 /* print nothing if the buffers are empty */
2298 if (trace_empty(iter))
2299 return;
2300 print_trace_header(m, iter);
2301 if (!(trace_flags & TRACE_ITER_VERBOSE))
2302 print_lat_help_header(m);
2303 } else {
2304 if (!(trace_flags & TRACE_ITER_VERBOSE)) {
2305 if (trace_flags & TRACE_ITER_IRQ_INFO)
2306 print_func_help_header_irq(iter->tr, m);
2307 else
2308 print_func_help_header(iter->tr, m);
2309 }
2310 }
2311}
2312
2313static void test_ftrace_alive(struct seq_file *m)
2314{
2315 if (!ftrace_is_dead())
2316 return;
2317 seq_printf(m, "# WARNING: FUNCTION TRACING IS CORRUPTED\n");
2318 seq_printf(m, "# MAY BE MISSING FUNCTION EVENTS\n");
2319}
2320
2321static int s_show(struct seq_file *m, void *v)
2322{
2323 struct trace_iterator *iter = v;
2324 int ret;
2325
2326 if (iter->ent == NULL) {
2327 if (iter->tr) {
2328 seq_printf(m, "# tracer: %s\n", iter->trace->name);
2329 seq_puts(m, "#\n");
2330 test_ftrace_alive(m);
2331 }
2332 if (iter->trace && iter->trace->print_header)
2333 iter->trace->print_header(m);
2334 else
2335 trace_default_header(m);
2336
2337 } else if (iter->leftover) {
2338 /*
2339 * If we filled the seq_file buffer earlier, we
2340 * want to just show it now.
2341 */
2342 ret = trace_print_seq(m, &iter->seq);
2343
2344 /* ret should this time be zero, but you never know */
2345 iter->leftover = ret;
2346
2347 } else {
2348 print_trace_line(iter);
2349 ret = trace_print_seq(m, &iter->seq);
2350 /*
2351 * If we overflow the seq_file buffer, then it will
2352 * ask us for this data again at start up.
2353 * Use that instead.
2354 * ret is 0 if seq_file write succeeded.
2355 * -1 otherwise.
2356 */
2357 iter->leftover = ret;
2358 }
2359
2360 return 0;
2361}
2362
2363static const struct seq_operations tracer_seq_ops = {
2364 .start = s_start,
2365 .next = s_next,
2366 .stop = s_stop,
2367 .show = s_show,
2368};
2369
2370static struct trace_iterator *
2371__tracing_open(struct inode *inode, struct file *file)
2372{
2373 long cpu_file = (long) inode->i_private;
2374 struct trace_iterator *iter;
2375 int cpu;
2376
2377 if (tracing_disabled)
2378 return ERR_PTR(-ENODEV);
2379
2380 iter = __seq_open_private(file, &tracer_seq_ops, sizeof(*iter));
2381 if (!iter)
2382 return ERR_PTR(-ENOMEM);
2383
2384 /*
2385 * We make a copy of the current tracer to avoid concurrent
2386 * changes on it while we are reading.
2387 */
2388 mutex_lock(&trace_types_lock);
2389 iter->trace = kzalloc(sizeof(*iter->trace), GFP_KERNEL);
2390 if (!iter->trace)
2391 goto fail;
2392
2393 if (current_trace)
2394 *iter->trace = *current_trace;
2395
2396 if (!zalloc_cpumask_var(&iter->started, GFP_KERNEL))
2397 goto fail;
2398
2399 if (current_trace && current_trace->print_max)
2400 iter->tr = &max_tr;
2401 else
2402 iter->tr = &global_trace;
2403 iter->pos = -1;
2404 mutex_init(&iter->mutex);
2405 iter->cpu_file = cpu_file;
2406
2407 /* Notify the tracer early; before we stop tracing. */
2408 if (iter->trace && iter->trace->open)
2409 iter->trace->open(iter);
2410
2411 /* Annotate start of buffers if we had overruns */
2412 if (ring_buffer_overruns(iter->tr->buffer))
2413 iter->iter_flags |= TRACE_FILE_ANNOTATE;
2414
2415 /* stop the trace while dumping */
2416 tracing_stop();
2417
2418 if (iter->cpu_file == TRACE_PIPE_ALL_CPU) {
2419 for_each_tracing_cpu(cpu) {
2420 iter->buffer_iter[cpu] =
2421 ring_buffer_read_prepare(iter->tr->buffer, cpu);
2422 }
2423 ring_buffer_read_prepare_sync();
2424 for_each_tracing_cpu(cpu) {
2425 ring_buffer_read_start(iter->buffer_iter[cpu]);
2426 tracing_iter_reset(iter, cpu);
2427 }
2428 } else {
2429 cpu = iter->cpu_file;
2430 iter->buffer_iter[cpu] =
2431 ring_buffer_read_prepare(iter->tr->buffer, cpu);
2432 ring_buffer_read_prepare_sync();
2433 ring_buffer_read_start(iter->buffer_iter[cpu]);
2434 tracing_iter_reset(iter, cpu);
2435 }
2436
2437 mutex_unlock(&trace_types_lock);
2438
2439 return iter;
2440
2441 fail:
2442 mutex_unlock(&trace_types_lock);
2443 kfree(iter->trace);
2444 seq_release_private(inode, file);
2445 return ERR_PTR(-ENOMEM);
2446}
2447
2448int tracing_open_generic(struct inode *inode, struct file *filp)
2449{
2450 if (tracing_disabled)
2451 return -ENODEV;
2452
2453 filp->private_data = inode->i_private;
2454 return 0;
2455}
2456
2457static int tracing_release(struct inode *inode, struct file *file)
2458{
2459 struct seq_file *m = file->private_data;
2460 struct trace_iterator *iter;
2461 int cpu;
2462
2463 if (!(file->f_mode & FMODE_READ))
2464 return 0;
2465
2466 iter = m->private;
2467
2468 mutex_lock(&trace_types_lock);
2469 for_each_tracing_cpu(cpu) {
2470 if (iter->buffer_iter[cpu])
2471 ring_buffer_read_finish(iter->buffer_iter[cpu]);
2472 }
2473
2474 if (iter->trace && iter->trace->close)
2475 iter->trace->close(iter);
2476
2477 /* reenable tracing if it was previously enabled */
2478 tracing_start();
2479 mutex_unlock(&trace_types_lock);
2480
2481 mutex_destroy(&iter->mutex);
2482 free_cpumask_var(iter->started);
2483 kfree(iter->trace);
2484 seq_release_private(inode, file);
2485 return 0;
2486}
2487
2488static int tracing_open(struct inode *inode, struct file *file)
2489{
2490 struct trace_iterator *iter;
2491 int ret = 0;
2492
2493 /* If this file was open for write, then erase contents */
2494 if ((file->f_mode & FMODE_WRITE) &&
2495 (file->f_flags & O_TRUNC)) {
2496 long cpu = (long) inode->i_private;
2497
2498 if (cpu == TRACE_PIPE_ALL_CPU)
2499 tracing_reset_online_cpus(&global_trace);
2500 else
2501 tracing_reset(&global_trace, cpu);
2502 }
2503
2504 if (file->f_mode & FMODE_READ) {
2505 iter = __tracing_open(inode, file);
2506 if (IS_ERR(iter))
2507 ret = PTR_ERR(iter);
2508 else if (trace_flags & TRACE_ITER_LATENCY_FMT)
2509 iter->iter_flags |= TRACE_FILE_LAT_FMT;
2510 }
2511 return ret;
2512}
2513
2514static void *
2515t_next(struct seq_file *m, void *v, loff_t *pos)
2516{
2517 struct tracer *t = v;
2518
2519 (*pos)++;
2520
2521 if (t)
2522 t = t->next;
2523
2524 return t;
2525}
2526
2527static void *t_start(struct seq_file *m, loff_t *pos)
2528{
2529 struct tracer *t;
2530 loff_t l = 0;
2531
2532 mutex_lock(&trace_types_lock);
2533 for (t = trace_types; t && l < *pos; t = t_next(m, t, &l))
2534 ;
2535
2536 return t;
2537}
2538
2539static void t_stop(struct seq_file *m, void *p)
2540{
2541 mutex_unlock(&trace_types_lock);
2542}
2543
2544static int t_show(struct seq_file *m, void *v)
2545{
2546 struct tracer *t = v;
2547
2548 if (!t)
2549 return 0;
2550
2551 seq_printf(m, "%s", t->name);
2552 if (t->next)
2553 seq_putc(m, ' ');
2554 else
2555 seq_putc(m, '\n');
2556
2557 return 0;
2558}
2559
2560static const struct seq_operations show_traces_seq_ops = {
2561 .start = t_start,
2562 .next = t_next,
2563 .stop = t_stop,
2564 .show = t_show,
2565};
2566
2567static int show_traces_open(struct inode *inode, struct file *file)
2568{
2569 if (tracing_disabled)
2570 return -ENODEV;
2571
2572 return seq_open(file, &show_traces_seq_ops);
2573}
2574
2575static ssize_t
2576tracing_write_stub(struct file *filp, const char __user *ubuf,
2577 size_t count, loff_t *ppos)
2578{
2579 return count;
2580}
2581
2582static loff_t tracing_seek(struct file *file, loff_t offset, int origin)
2583{
2584 if (file->f_mode & FMODE_READ)
2585 return seq_lseek(file, offset, origin);
2586 else
2587 return 0;
2588}
2589
2590static const struct file_operations tracing_fops = {
2591 .open = tracing_open,
2592 .read = seq_read,
2593 .write = tracing_write_stub,
2594 .llseek = tracing_seek,
2595 .release = tracing_release,
2596};
2597
2598static const struct file_operations show_traces_fops = {
2599 .open = show_traces_open,
2600 .read = seq_read,
2601 .release = seq_release,
2602 .llseek = seq_lseek,
2603};
2604
2605/*
2606 * Only trace on a CPU if the bitmask is set:
2607 */
2608static cpumask_var_t tracing_cpumask;
2609
2610/*
2611 * The tracer itself will not take this lock, but still we want
2612 * to provide a consistent cpumask to user-space:
2613 */
2614static DEFINE_MUTEX(tracing_cpumask_update_lock);
2615
2616/*
2617 * Temporary storage for the character representation of the
2618 * CPU bitmask (and one more byte for the newline):
2619 */
2620static char mask_str[NR_CPUS + 1];
2621
2622static ssize_t
2623tracing_cpumask_read(struct file *filp, char __user *ubuf,
2624 size_t count, loff_t *ppos)
2625{
2626 int len;
2627
2628 mutex_lock(&tracing_cpumask_update_lock);
2629
2630 len = cpumask_scnprintf(mask_str, count, tracing_cpumask);
2631 if (count - len < 2) {
2632 count = -EINVAL;
2633 goto out_err;
2634 }
2635 len += sprintf(mask_str + len, "\n");
2636 count = simple_read_from_buffer(ubuf, count, ppos, mask_str, NR_CPUS+1);
2637
2638out_err:
2639 mutex_unlock(&tracing_cpumask_update_lock);
2640
2641 return count;
2642}
2643
2644static ssize_t
2645tracing_cpumask_write(struct file *filp, const char __user *ubuf,
2646 size_t count, loff_t *ppos)
2647{
2648 int err, cpu;
2649 cpumask_var_t tracing_cpumask_new;
2650
2651 if (!alloc_cpumask_var(&tracing_cpumask_new, GFP_KERNEL))
2652 return -ENOMEM;
2653
2654 err = cpumask_parse_user(ubuf, count, tracing_cpumask_new);
2655 if (err)
2656 goto err_unlock;
2657
2658 mutex_lock(&tracing_cpumask_update_lock);
2659
2660 local_irq_disable();
2661 arch_spin_lock(&ftrace_max_lock);
2662 for_each_tracing_cpu(cpu) {
2663 /*
2664 * Increase/decrease the disabled counter if we are
2665 * about to flip a bit in the cpumask:
2666 */
2667 if (cpumask_test_cpu(cpu, tracing_cpumask) &&
2668 !cpumask_test_cpu(cpu, tracing_cpumask_new)) {
2669 atomic_inc(&global_trace.data[cpu]->disabled);
2670 ring_buffer_record_disable_cpu(global_trace.buffer, cpu);
2671 }
2672 if (!cpumask_test_cpu(cpu, tracing_cpumask) &&
2673 cpumask_test_cpu(cpu, tracing_cpumask_new)) {
2674 atomic_dec(&global_trace.data[cpu]->disabled);
2675 ring_buffer_record_enable_cpu(global_trace.buffer, cpu);
2676 }
2677 }
2678 arch_spin_unlock(&ftrace_max_lock);
2679 local_irq_enable();
2680
2681 cpumask_copy(tracing_cpumask, tracing_cpumask_new);
2682
2683 mutex_unlock(&tracing_cpumask_update_lock);
2684 free_cpumask_var(tracing_cpumask_new);
2685
2686 return count;
2687
2688err_unlock:
2689 free_cpumask_var(tracing_cpumask_new);
2690
2691 return err;
2692}
2693
2694static const struct file_operations tracing_cpumask_fops = {
2695 .open = tracing_open_generic,
2696 .read = tracing_cpumask_read,
2697 .write = tracing_cpumask_write,
2698 .llseek = generic_file_llseek,
2699};
2700
2701static int tracing_trace_options_show(struct seq_file *m, void *v)
2702{
2703 struct tracer_opt *trace_opts;
2704 u32 tracer_flags;
2705 int i;
2706
2707 mutex_lock(&trace_types_lock);
2708 tracer_flags = current_trace->flags->val;
2709 trace_opts = current_trace->flags->opts;
2710
2711 for (i = 0; trace_options[i]; i++) {
2712 if (trace_flags & (1 << i))
2713 seq_printf(m, "%s\n", trace_options[i]);
2714 else
2715 seq_printf(m, "no%s\n", trace_options[i]);
2716 }
2717
2718 for (i = 0; trace_opts[i].name; i++) {
2719 if (tracer_flags & trace_opts[i].bit)
2720 seq_printf(m, "%s\n", trace_opts[i].name);
2721 else
2722 seq_printf(m, "no%s\n", trace_opts[i].name);
2723 }
2724 mutex_unlock(&trace_types_lock);
2725
2726 return 0;
2727}
2728
2729static int __set_tracer_option(struct tracer *trace,
2730 struct tracer_flags *tracer_flags,
2731 struct tracer_opt *opts, int neg)
2732{
2733 int ret;
2734
2735 ret = trace->set_flag(tracer_flags->val, opts->bit, !neg);
2736 if (ret)
2737 return ret;
2738
2739 if (neg)
2740 tracer_flags->val &= ~opts->bit;
2741 else
2742 tracer_flags->val |= opts->bit;
2743 return 0;
2744}
2745
2746/* Try to assign a tracer specific option */
2747static int set_tracer_option(struct tracer *trace, char *cmp, int neg)
2748{
2749 struct tracer_flags *tracer_flags = trace->flags;
2750 struct tracer_opt *opts = NULL;
2751 int i;
2752
2753 for (i = 0; tracer_flags->opts[i].name; i++) {
2754 opts = &tracer_flags->opts[i];
2755
2756 if (strcmp(cmp, opts->name) == 0)
2757 return __set_tracer_option(trace, trace->flags,
2758 opts, neg);
2759 }
2760
2761 return -EINVAL;
2762}
2763
2764static void set_tracer_flags(unsigned int mask, int enabled)
2765{
2766 /* do nothing if flag is already set */
2767 if (!!(trace_flags & mask) == !!enabled)
2768 return;
2769
2770 if (enabled)
2771 trace_flags |= mask;
2772 else
2773 trace_flags &= ~mask;
2774
2775 if (mask == TRACE_ITER_RECORD_CMD)
2776 trace_event_enable_cmd_record(enabled);
2777
2778 if (mask == TRACE_ITER_OVERWRITE)
2779 ring_buffer_change_overwrite(global_trace.buffer, enabled);
2780}
2781
2782static ssize_t
2783tracing_trace_options_write(struct file *filp, const char __user *ubuf,
2784 size_t cnt, loff_t *ppos)
2785{
2786 char buf[64];
2787 char *cmp;
2788 int neg = 0;
2789 int ret;
2790 int i;
2791
2792 if (cnt >= sizeof(buf))
2793 return -EINVAL;
2794
2795 if (copy_from_user(&buf, ubuf, cnt))
2796 return -EFAULT;
2797
2798 buf[cnt] = 0;
2799 cmp = strstrip(buf);
2800
2801 if (strncmp(cmp, "no", 2) == 0) {
2802 neg = 1;
2803 cmp += 2;
2804 }
2805
2806 for (i = 0; trace_options[i]; i++) {
2807 if (strcmp(cmp, trace_options[i]) == 0) {
2808 set_tracer_flags(1 << i, !neg);
2809 break;
2810 }
2811 }
2812
2813 /* If no option could be set, test the specific tracer options */
2814 if (!trace_options[i]) {
2815 mutex_lock(&trace_types_lock);
2816 ret = set_tracer_option(current_trace, cmp, neg);
2817 mutex_unlock(&trace_types_lock);
2818 if (ret)
2819 return ret;
2820 }
2821
2822 *ppos += cnt;
2823
2824 return cnt;
2825}
2826
2827static int tracing_trace_options_open(struct inode *inode, struct file *file)
2828{
2829 if (tracing_disabled)
2830 return -ENODEV;
2831 return single_open(file, tracing_trace_options_show, NULL);
2832}
2833
2834static const struct file_operations tracing_iter_fops = {
2835 .open = tracing_trace_options_open,
2836 .read = seq_read,
2837 .llseek = seq_lseek,
2838 .release = single_release,
2839 .write = tracing_trace_options_write,
2840};
2841
2842static const char readme_msg[] =
2843 "tracing mini-HOWTO:\n\n"
2844 "# mount -t debugfs nodev /sys/kernel/debug\n\n"
2845 "# cat /sys/kernel/debug/tracing/available_tracers\n"
2846 "wakeup wakeup_rt preemptirqsoff preemptoff irqsoff function nop\n\n"
2847 "# cat /sys/kernel/debug/tracing/current_tracer\n"
2848 "nop\n"
2849 "# echo wakeup > /sys/kernel/debug/tracing/current_tracer\n"
2850 "# cat /sys/kernel/debug/tracing/current_tracer\n"
2851 "wakeup\n"
2852 "# cat /sys/kernel/debug/tracing/trace_options\n"
2853 "noprint-parent nosym-offset nosym-addr noverbose\n"
2854 "# echo print-parent > /sys/kernel/debug/tracing/trace_options\n"
2855 "# echo 1 > /sys/kernel/debug/tracing/tracing_on\n"
2856 "# cat /sys/kernel/debug/tracing/trace > /tmp/trace.txt\n"
2857 "# echo 0 > /sys/kernel/debug/tracing/tracing_on\n"
2858;
2859
2860static ssize_t
2861tracing_readme_read(struct file *filp, char __user *ubuf,
2862 size_t cnt, loff_t *ppos)
2863{
2864 return simple_read_from_buffer(ubuf, cnt, ppos,
2865 readme_msg, strlen(readme_msg));
2866}
2867
2868static const struct file_operations tracing_readme_fops = {
2869 .open = tracing_open_generic,
2870 .read = tracing_readme_read,
2871 .llseek = generic_file_llseek,
2872};
2873
2874static ssize_t
2875tracing_saved_cmdlines_read(struct file *file, char __user *ubuf,
2876 size_t cnt, loff_t *ppos)
2877{
2878 char *buf_comm;
2879 char *file_buf;
2880 char *buf;
2881 int len = 0;
2882 int pid;
2883 int i;
2884
2885 file_buf = kmalloc(SAVED_CMDLINES*(16+TASK_COMM_LEN), GFP_KERNEL);
2886 if (!file_buf)
2887 return -ENOMEM;
2888
2889 buf_comm = kmalloc(TASK_COMM_LEN, GFP_KERNEL);
2890 if (!buf_comm) {
2891 kfree(file_buf);
2892 return -ENOMEM;
2893 }
2894
2895 buf = file_buf;
2896
2897 for (i = 0; i < SAVED_CMDLINES; i++) {
2898 int r;
2899
2900 pid = map_cmdline_to_pid[i];
2901 if (pid == -1 || pid == NO_CMDLINE_MAP)
2902 continue;
2903
2904 trace_find_cmdline(pid, buf_comm);
2905 r = sprintf(buf, "%d %s\n", pid, buf_comm);
2906 buf += r;
2907 len += r;
2908 }
2909
2910 len = simple_read_from_buffer(ubuf, cnt, ppos,
2911 file_buf, len);
2912
2913 kfree(file_buf);
2914 kfree(buf_comm);
2915
2916 return len;
2917}
2918
2919static const struct file_operations tracing_saved_cmdlines_fops = {
2920 .open = tracing_open_generic,
2921 .read = tracing_saved_cmdlines_read,
2922 .llseek = generic_file_llseek,
2923};
2924
2925static ssize_t
2926tracing_ctrl_read(struct file *filp, char __user *ubuf,
2927 size_t cnt, loff_t *ppos)
2928{
2929 char buf[64];
2930 int r;
2931
2932 r = sprintf(buf, "%u\n", tracer_enabled);
2933 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2934}
2935
2936static ssize_t
2937tracing_ctrl_write(struct file *filp, const char __user *ubuf,
2938 size_t cnt, loff_t *ppos)
2939{
2940 struct trace_array *tr = filp->private_data;
2941 unsigned long val;
2942 int ret;
2943
2944 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
2945 if (ret)
2946 return ret;
2947
2948 val = !!val;
2949
2950 mutex_lock(&trace_types_lock);
2951 if (tracer_enabled ^ val) {
2952
2953 /* Only need to warn if this is used to change the state */
2954 WARN_ONCE(1, "tracing_enabled is deprecated. Use tracing_on");
2955
2956 if (val) {
2957 tracer_enabled = 1;
2958 if (current_trace->start)
2959 current_trace->start(tr);
2960 tracing_start();
2961 } else {
2962 tracer_enabled = 0;
2963 tracing_stop();
2964 if (current_trace->stop)
2965 current_trace->stop(tr);
2966 }
2967 }
2968 mutex_unlock(&trace_types_lock);
2969
2970 *ppos += cnt;
2971
2972 return cnt;
2973}
2974
2975static ssize_t
2976tracing_set_trace_read(struct file *filp, char __user *ubuf,
2977 size_t cnt, loff_t *ppos)
2978{
2979 char buf[MAX_TRACER_SIZE+2];
2980 int r;
2981
2982 mutex_lock(&trace_types_lock);
2983 if (current_trace)
2984 r = sprintf(buf, "%s\n", current_trace->name);
2985 else
2986 r = sprintf(buf, "\n");
2987 mutex_unlock(&trace_types_lock);
2988
2989 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
2990}
2991
2992int tracer_init(struct tracer *t, struct trace_array *tr)
2993{
2994 tracing_reset_online_cpus(tr);
2995 return t->init(tr);
2996}
2997
2998static void set_buffer_entries(struct trace_array *tr, unsigned long val)
2999{
3000 int cpu;
3001 for_each_tracing_cpu(cpu)
3002 tr->data[cpu]->entries = val;
3003}
3004
3005static int __tracing_resize_ring_buffer(unsigned long size, int cpu)
3006{
3007 int ret;
3008
3009 /*
3010 * If kernel or user changes the size of the ring buffer
3011 * we use the size that was given, and we can forget about
3012 * expanding it later.
3013 */
3014 ring_buffer_expanded = 1;
3015
3016 ret = ring_buffer_resize(global_trace.buffer, size, cpu);
3017 if (ret < 0)
3018 return ret;
3019
3020 if (!current_trace->use_max_tr)
3021 goto out;
3022
3023 ret = ring_buffer_resize(max_tr.buffer, size, cpu);
3024 if (ret < 0) {
3025 int r = 0;
3026
3027 if (cpu == RING_BUFFER_ALL_CPUS) {
3028 int i;
3029 for_each_tracing_cpu(i) {
3030 r = ring_buffer_resize(global_trace.buffer,
3031 global_trace.data[i]->entries,
3032 i);
3033 if (r < 0)
3034 break;
3035 }
3036 } else {
3037 r = ring_buffer_resize(global_trace.buffer,
3038 global_trace.data[cpu]->entries,
3039 cpu);
3040 }
3041
3042 if (r < 0) {
3043 /*
3044 * AARGH! We are left with different
3045 * size max buffer!!!!
3046 * The max buffer is our "snapshot" buffer.
3047 * When a tracer needs a snapshot (one of the
3048 * latency tracers), it swaps the max buffer
3049 * with the saved snap shot. We succeeded to
3050 * update the size of the main buffer, but failed to
3051 * update the size of the max buffer. But when we tried
3052 * to reset the main buffer to the original size, we
3053 * failed there too. This is very unlikely to
3054 * happen, but if it does, warn and kill all
3055 * tracing.
3056 */
3057 WARN_ON(1);
3058 tracing_disabled = 1;
3059 }
3060 return ret;
3061 }
3062
3063 if (cpu == RING_BUFFER_ALL_CPUS)
3064 set_buffer_entries(&max_tr, size);
3065 else
3066 max_tr.data[cpu]->entries = size;
3067
3068 out:
3069 if (cpu == RING_BUFFER_ALL_CPUS)
3070 set_buffer_entries(&global_trace, size);
3071 else
3072 global_trace.data[cpu]->entries = size;
3073
3074 return ret;
3075}
3076
3077static ssize_t tracing_resize_ring_buffer(unsigned long size, int cpu_id)
3078{
3079 int ret = size;
3080
3081 mutex_lock(&trace_types_lock);
3082
3083 if (cpu_id != RING_BUFFER_ALL_CPUS) {
3084 /* make sure, this cpu is enabled in the mask */
3085 if (!cpumask_test_cpu(cpu_id, tracing_buffer_mask)) {
3086 ret = -EINVAL;
3087 goto out;
3088 }
3089 }
3090
3091 ret = __tracing_resize_ring_buffer(size, cpu_id);
3092 if (ret < 0)
3093 ret = -ENOMEM;
3094
3095out:
3096 mutex_unlock(&trace_types_lock);
3097
3098 return ret;
3099}
3100
3101
3102/**
3103 * tracing_update_buffers - used by tracing facility to expand ring buffers
3104 *
3105 * To save on memory when the tracing is never used on a system with it
3106 * configured in. The ring buffers are set to a minimum size. But once
3107 * a user starts to use the tracing facility, then they need to grow
3108 * to their default size.
3109 *
3110 * This function is to be called when a tracer is about to be used.
3111 */
3112int tracing_update_buffers(void)
3113{
3114 int ret = 0;
3115
3116 mutex_lock(&trace_types_lock);
3117 if (!ring_buffer_expanded)
3118 ret = __tracing_resize_ring_buffer(trace_buf_size,
3119 RING_BUFFER_ALL_CPUS);
3120 mutex_unlock(&trace_types_lock);
3121
3122 return ret;
3123}
3124
3125struct trace_option_dentry;
3126
3127static struct trace_option_dentry *
3128create_trace_option_files(struct tracer *tracer);
3129
3130static void
3131destroy_trace_option_files(struct trace_option_dentry *topts);
3132
3133static int tracing_set_tracer(const char *buf)
3134{
3135 static struct trace_option_dentry *topts;
3136 struct trace_array *tr = &global_trace;
3137 struct tracer *t;
3138 int ret = 0;
3139
3140 mutex_lock(&trace_types_lock);
3141
3142 if (!ring_buffer_expanded) {
3143 ret = __tracing_resize_ring_buffer(trace_buf_size,
3144 RING_BUFFER_ALL_CPUS);
3145 if (ret < 0)
3146 goto out;
3147 ret = 0;
3148 }
3149
3150 for (t = trace_types; t; t = t->next) {
3151 if (strcmp(t->name, buf) == 0)
3152 break;
3153 }
3154 if (!t) {
3155 ret = -EINVAL;
3156 goto out;
3157 }
3158 if (t == current_trace)
3159 goto out;
3160
3161 trace_branch_disable();
3162 if (current_trace && current_trace->reset)
3163 current_trace->reset(tr);
3164 if (current_trace && current_trace->use_max_tr) {
3165 /*
3166 * We don't free the ring buffer. instead, resize it because
3167 * The max_tr ring buffer has some state (e.g. ring->clock) and
3168 * we want preserve it.
3169 */
3170 ring_buffer_resize(max_tr.buffer, 1, RING_BUFFER_ALL_CPUS);
3171 set_buffer_entries(&max_tr, 1);
3172 }
3173 destroy_trace_option_files(topts);
3174
3175 current_trace = t;
3176
3177 topts = create_trace_option_files(current_trace);
3178 if (current_trace->use_max_tr) {
3179 int cpu;
3180 /* we need to make per cpu buffer sizes equivalent */
3181 for_each_tracing_cpu(cpu) {
3182 ret = ring_buffer_resize(max_tr.buffer,
3183 global_trace.data[cpu]->entries,
3184 cpu);
3185 if (ret < 0)
3186 goto out;
3187 max_tr.data[cpu]->entries =
3188 global_trace.data[cpu]->entries;
3189 }
3190 }
3191
3192 if (t->init) {
3193 ret = tracer_init(t, tr);
3194 if (ret)
3195 goto out;
3196 }
3197
3198 trace_branch_enable(tr);
3199 out:
3200 mutex_unlock(&trace_types_lock);
3201
3202 return ret;
3203}
3204
3205static ssize_t
3206tracing_set_trace_write(struct file *filp, const char __user *ubuf,
3207 size_t cnt, loff_t *ppos)
3208{
3209 char buf[MAX_TRACER_SIZE+1];
3210 int i;
3211 size_t ret;
3212 int err;
3213
3214 ret = cnt;
3215
3216 if (cnt > MAX_TRACER_SIZE)
3217 cnt = MAX_TRACER_SIZE;
3218
3219 if (copy_from_user(&buf, ubuf, cnt))
3220 return -EFAULT;
3221
3222 buf[cnt] = 0;
3223
3224 /* strip ending whitespace. */
3225 for (i = cnt - 1; i > 0 && isspace(buf[i]); i--)
3226 buf[i] = 0;
3227
3228 err = tracing_set_tracer(buf);
3229 if (err)
3230 return err;
3231
3232 *ppos += ret;
3233
3234 return ret;
3235}
3236
3237static ssize_t
3238tracing_max_lat_read(struct file *filp, char __user *ubuf,
3239 size_t cnt, loff_t *ppos)
3240{
3241 unsigned long *ptr = filp->private_data;
3242 char buf[64];
3243 int r;
3244
3245 r = snprintf(buf, sizeof(buf), "%ld\n",
3246 *ptr == (unsigned long)-1 ? -1 : nsecs_to_usecs(*ptr));
3247 if (r > sizeof(buf))
3248 r = sizeof(buf);
3249 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
3250}
3251
3252static ssize_t
3253tracing_max_lat_write(struct file *filp, const char __user *ubuf,
3254 size_t cnt, loff_t *ppos)
3255{
3256 unsigned long *ptr = filp->private_data;
3257 unsigned long val;
3258 int ret;
3259
3260 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
3261 if (ret)
3262 return ret;
3263
3264 *ptr = val * 1000;
3265
3266 return cnt;
3267}
3268
3269static int tracing_open_pipe(struct inode *inode, struct file *filp)
3270{
3271 long cpu_file = (long) inode->i_private;
3272 struct trace_iterator *iter;
3273 int ret = 0;
3274
3275 if (tracing_disabled)
3276 return -ENODEV;
3277
3278 mutex_lock(&trace_types_lock);
3279
3280 /* create a buffer to store the information to pass to userspace */
3281 iter = kzalloc(sizeof(*iter), GFP_KERNEL);
3282 if (!iter) {
3283 ret = -ENOMEM;
3284 goto out;
3285 }
3286
3287 /*
3288 * We make a copy of the current tracer to avoid concurrent
3289 * changes on it while we are reading.
3290 */
3291 iter->trace = kmalloc(sizeof(*iter->trace), GFP_KERNEL);
3292 if (!iter->trace) {
3293 ret = -ENOMEM;
3294 goto fail;
3295 }
3296 if (current_trace)
3297 *iter->trace = *current_trace;
3298
3299 if (!alloc_cpumask_var(&iter->started, GFP_KERNEL)) {
3300 ret = -ENOMEM;
3301 goto fail;
3302 }
3303
3304 /* trace pipe does not show start of buffer */
3305 cpumask_setall(iter->started);
3306
3307 if (trace_flags & TRACE_ITER_LATENCY_FMT)
3308 iter->iter_flags |= TRACE_FILE_LAT_FMT;
3309
3310 iter->cpu_file = cpu_file;
3311 iter->tr = &global_trace;
3312 mutex_init(&iter->mutex);
3313 filp->private_data = iter;
3314
3315 if (iter->trace->pipe_open)
3316 iter->trace->pipe_open(iter);
3317
3318 nonseekable_open(inode, filp);
3319out:
3320 mutex_unlock(&trace_types_lock);
3321 return ret;
3322
3323fail:
3324 kfree(iter->trace);
3325 kfree(iter);
3326 mutex_unlock(&trace_types_lock);
3327 return ret;
3328}
3329
3330static int tracing_release_pipe(struct inode *inode, struct file *file)
3331{
3332 struct trace_iterator *iter = file->private_data;
3333
3334 mutex_lock(&trace_types_lock);
3335
3336 if (iter->trace->pipe_close)
3337 iter->trace->pipe_close(iter);
3338
3339 mutex_unlock(&trace_types_lock);
3340
3341 free_cpumask_var(iter->started);
3342 mutex_destroy(&iter->mutex);
3343 kfree(iter->trace);
3344 kfree(iter);
3345
3346 return 0;
3347}
3348
3349static unsigned int
3350tracing_poll_pipe(struct file *filp, poll_table *poll_table)
3351{
3352 struct trace_iterator *iter = filp->private_data;
3353
3354 if (trace_flags & TRACE_ITER_BLOCK) {
3355 /*
3356 * Always select as readable when in blocking mode
3357 */
3358 return POLLIN | POLLRDNORM;
3359 } else {
3360 if (!trace_empty(iter))
3361 return POLLIN | POLLRDNORM;
3362 poll_wait(filp, &trace_wait, poll_table);
3363 if (!trace_empty(iter))
3364 return POLLIN | POLLRDNORM;
3365
3366 return 0;
3367 }
3368}
3369
3370
3371void default_wait_pipe(struct trace_iterator *iter)
3372{
3373 DEFINE_WAIT(wait);
3374
3375 prepare_to_wait(&trace_wait, &wait, TASK_INTERRUPTIBLE);
3376
3377 if (trace_empty(iter))
3378 schedule();
3379
3380 finish_wait(&trace_wait, &wait);
3381}
3382
3383/*
3384 * This is a make-shift waitqueue.
3385 * A tracer might use this callback on some rare cases:
3386 *
3387 * 1) the current tracer might hold the runqueue lock when it wakes up
3388 * a reader, hence a deadlock (sched, function, and function graph tracers)
3389 * 2) the function tracers, trace all functions, we don't want
3390 * the overhead of calling wake_up and friends
3391 * (and tracing them too)
3392 *
3393 * Anyway, this is really very primitive wakeup.
3394 */
3395void poll_wait_pipe(struct trace_iterator *iter)
3396{
3397 set_current_state(TASK_INTERRUPTIBLE);
3398 /* sleep for 100 msecs, and try again. */
3399 schedule_timeout(HZ / 10);
3400}
3401
3402/* Must be called with trace_types_lock mutex held. */
3403static int tracing_wait_pipe(struct file *filp)
3404{
3405 struct trace_iterator *iter = filp->private_data;
3406
3407 while (trace_empty(iter)) {
3408
3409 if ((filp->f_flags & O_NONBLOCK)) {
3410 return -EAGAIN;
3411 }
3412
3413 mutex_unlock(&iter->mutex);
3414
3415 iter->trace->wait_pipe(iter);
3416
3417 mutex_lock(&iter->mutex);
3418
3419 if (signal_pending(current))
3420 return -EINTR;
3421
3422 /*
3423 * We block until we read something and tracing is disabled.
3424 * We still block if tracing is disabled, but we have never
3425 * read anything. This allows a user to cat this file, and
3426 * then enable tracing. But after we have read something,
3427 * we give an EOF when tracing is again disabled.
3428 *
3429 * iter->pos will be 0 if we haven't read anything.
3430 */
3431 if (!tracer_enabled && iter->pos)
3432 break;
3433 }
3434
3435 return 1;
3436}
3437
3438/*
3439 * Consumer reader.
3440 */
3441static ssize_t
3442tracing_read_pipe(struct file *filp, char __user *ubuf,
3443 size_t cnt, loff_t *ppos)
3444{
3445 struct trace_iterator *iter = filp->private_data;
3446 static struct tracer *old_tracer;
3447 ssize_t sret;
3448
3449 /* return any leftover data */
3450 sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
3451 if (sret != -EBUSY)
3452 return sret;
3453
3454 trace_seq_init(&iter->seq);
3455
3456 /* copy the tracer to avoid using a global lock all around */
3457 mutex_lock(&trace_types_lock);
3458 if (unlikely(old_tracer != current_trace && current_trace)) {
3459 old_tracer = current_trace;
3460 *iter->trace = *current_trace;
3461 }
3462 mutex_unlock(&trace_types_lock);
3463
3464 /*
3465 * Avoid more than one consumer on a single file descriptor
3466 * This is just a matter of traces coherency, the ring buffer itself
3467 * is protected.
3468 */
3469 mutex_lock(&iter->mutex);
3470 if (iter->trace->read) {
3471 sret = iter->trace->read(iter, filp, ubuf, cnt, ppos);
3472 if (sret)
3473 goto out;
3474 }
3475
3476waitagain:
3477 sret = tracing_wait_pipe(filp);
3478 if (sret <= 0)
3479 goto out;
3480
3481 /* stop when tracing is finished */
3482 if (trace_empty(iter)) {
3483 sret = 0;
3484 goto out;
3485 }
3486
3487 if (cnt >= PAGE_SIZE)
3488 cnt = PAGE_SIZE - 1;
3489
3490 /* reset all but tr, trace, and overruns */
3491 memset(&iter->seq, 0,
3492 sizeof(struct trace_iterator) -
3493 offsetof(struct trace_iterator, seq));
3494 iter->pos = -1;
3495
3496 trace_event_read_lock();
3497 trace_access_lock(iter->cpu_file);
3498 while (trace_find_next_entry_inc(iter) != NULL) {
3499 enum print_line_t ret;
3500 int len = iter->seq.len;
3501
3502 ret = print_trace_line(iter);
3503 if (ret == TRACE_TYPE_PARTIAL_LINE) {
3504 /* don't print partial lines */
3505 iter->seq.len = len;
3506 break;
3507 }
3508 if (ret != TRACE_TYPE_NO_CONSUME)
3509 trace_consume(iter);
3510
3511 if (iter->seq.len >= cnt)
3512 break;
3513
3514 /*
3515 * Setting the full flag means we reached the trace_seq buffer
3516 * size and we should leave by partial output condition above.
3517 * One of the trace_seq_* functions is not used properly.
3518 */
3519 WARN_ONCE(iter->seq.full, "full flag set for trace type %d",
3520 iter->ent->type);
3521 }
3522 trace_access_unlock(iter->cpu_file);
3523 trace_event_read_unlock();
3524
3525 /* Now copy what we have to the user */
3526 sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
3527 if (iter->seq.readpos >= iter->seq.len)
3528 trace_seq_init(&iter->seq);
3529
3530 /*
3531 * If there was nothing to send to user, in spite of consuming trace
3532 * entries, go back to wait for more entries.
3533 */
3534 if (sret == -EBUSY)
3535 goto waitagain;
3536
3537out:
3538 mutex_unlock(&iter->mutex);
3539
3540 return sret;
3541}
3542
3543static void tracing_pipe_buf_release(struct pipe_inode_info *pipe,
3544 struct pipe_buffer *buf)
3545{
3546 __free_page(buf->page);
3547}
3548
3549static void tracing_spd_release_pipe(struct splice_pipe_desc *spd,
3550 unsigned int idx)
3551{
3552 __free_page(spd->pages[idx]);
3553}
3554
3555static const struct pipe_buf_operations tracing_pipe_buf_ops = {
3556 .can_merge = 0,
3557 .map = generic_pipe_buf_map,
3558 .unmap = generic_pipe_buf_unmap,
3559 .confirm = generic_pipe_buf_confirm,
3560 .release = tracing_pipe_buf_release,
3561 .steal = generic_pipe_buf_steal,
3562 .get = generic_pipe_buf_get,
3563};
3564
3565static size_t
3566tracing_fill_pipe_page(size_t rem, struct trace_iterator *iter)
3567{
3568 size_t count;
3569 int ret;
3570
3571 /* Seq buffer is page-sized, exactly what we need. */
3572 for (;;) {
3573 count = iter->seq.len;
3574 ret = print_trace_line(iter);
3575 count = iter->seq.len - count;
3576 if (rem < count) {
3577 rem = 0;
3578 iter->seq.len -= count;
3579 break;
3580 }
3581 if (ret == TRACE_TYPE_PARTIAL_LINE) {
3582 iter->seq.len -= count;
3583 break;
3584 }
3585
3586 if (ret != TRACE_TYPE_NO_CONSUME)
3587 trace_consume(iter);
3588 rem -= count;
3589 if (!trace_find_next_entry_inc(iter)) {
3590 rem = 0;
3591 iter->ent = NULL;
3592 break;
3593 }
3594 }
3595
3596 return rem;
3597}
3598
3599static ssize_t tracing_splice_read_pipe(struct file *filp,
3600 loff_t *ppos,
3601 struct pipe_inode_info *pipe,
3602 size_t len,
3603 unsigned int flags)
3604{
3605 struct page *pages_def[PIPE_DEF_BUFFERS];
3606 struct partial_page partial_def[PIPE_DEF_BUFFERS];
3607 struct trace_iterator *iter = filp->private_data;
3608 struct splice_pipe_desc spd = {
3609 .pages = pages_def,
3610 .partial = partial_def,
3611 .nr_pages = 0, /* This gets updated below. */
3612 .nr_pages_max = PIPE_DEF_BUFFERS,
3613 .flags = flags,
3614 .ops = &tracing_pipe_buf_ops,
3615 .spd_release = tracing_spd_release_pipe,
3616 };
3617 static struct tracer *old_tracer;
3618 ssize_t ret;
3619 size_t rem;
3620 unsigned int i;
3621
3622 if (splice_grow_spd(pipe, &spd))
3623 return -ENOMEM;
3624
3625 /* copy the tracer to avoid using a global lock all around */
3626 mutex_lock(&trace_types_lock);
3627 if (unlikely(old_tracer != current_trace && current_trace)) {
3628 old_tracer = current_trace;
3629 *iter->trace = *current_trace;
3630 }
3631 mutex_unlock(&trace_types_lock);
3632
3633 mutex_lock(&iter->mutex);
3634
3635 if (iter->trace->splice_read) {
3636 ret = iter->trace->splice_read(iter, filp,
3637 ppos, pipe, len, flags);
3638 if (ret)
3639 goto out_err;
3640 }
3641
3642 ret = tracing_wait_pipe(filp);
3643 if (ret <= 0)
3644 goto out_err;
3645
3646 if (!iter->ent && !trace_find_next_entry_inc(iter)) {
3647 ret = -EFAULT;
3648 goto out_err;
3649 }
3650
3651 trace_event_read_lock();
3652 trace_access_lock(iter->cpu_file);
3653
3654 /* Fill as many pages as possible. */
3655 for (i = 0, rem = len; i < pipe->buffers && rem; i++) {
3656 spd.pages[i] = alloc_page(GFP_KERNEL);
3657 if (!spd.pages[i])
3658 break;
3659
3660 rem = tracing_fill_pipe_page(rem, iter);
3661
3662 /* Copy the data into the page, so we can start over. */
3663 ret = trace_seq_to_buffer(&iter->seq,
3664 page_address(spd.pages[i]),
3665 iter->seq.len);
3666 if (ret < 0) {
3667 __free_page(spd.pages[i]);
3668 break;
3669 }
3670 spd.partial[i].offset = 0;
3671 spd.partial[i].len = iter->seq.len;
3672
3673 trace_seq_init(&iter->seq);
3674 }
3675
3676 trace_access_unlock(iter->cpu_file);
3677 trace_event_read_unlock();
3678 mutex_unlock(&iter->mutex);
3679
3680 spd.nr_pages = i;
3681
3682 ret = splice_to_pipe(pipe, &spd);
3683out:
3684 splice_shrink_spd(&spd);
3685 return ret;
3686
3687out_err:
3688 mutex_unlock(&iter->mutex);
3689 goto out;
3690}
3691
3692struct ftrace_entries_info {
3693 struct trace_array *tr;
3694 int cpu;
3695};
3696
3697static int tracing_entries_open(struct inode *inode, struct file *filp)
3698{
3699 struct ftrace_entries_info *info;
3700
3701 if (tracing_disabled)
3702 return -ENODEV;
3703
3704 info = kzalloc(sizeof(*info), GFP_KERNEL);
3705 if (!info)
3706 return -ENOMEM;
3707
3708 info->tr = &global_trace;
3709 info->cpu = (unsigned long)inode->i_private;
3710
3711 filp->private_data = info;
3712
3713 return 0;
3714}
3715
3716static ssize_t
3717tracing_entries_read(struct file *filp, char __user *ubuf,
3718 size_t cnt, loff_t *ppos)
3719{
3720 struct ftrace_entries_info *info = filp->private_data;
3721 struct trace_array *tr = info->tr;
3722 char buf[64];
3723 int r = 0;
3724 ssize_t ret;
3725
3726 mutex_lock(&trace_types_lock);
3727
3728 if (info->cpu == RING_BUFFER_ALL_CPUS) {
3729 int cpu, buf_size_same;
3730 unsigned long size;
3731
3732 size = 0;
3733 buf_size_same = 1;
3734 /* check if all cpu sizes are same */
3735 for_each_tracing_cpu(cpu) {
3736 /* fill in the size from first enabled cpu */
3737 if (size == 0)
3738 size = tr->data[cpu]->entries;
3739 if (size != tr->data[cpu]->entries) {
3740 buf_size_same = 0;
3741 break;
3742 }
3743 }
3744
3745 if (buf_size_same) {
3746 if (!ring_buffer_expanded)
3747 r = sprintf(buf, "%lu (expanded: %lu)\n",
3748 size >> 10,
3749 trace_buf_size >> 10);
3750 else
3751 r = sprintf(buf, "%lu\n", size >> 10);
3752 } else
3753 r = sprintf(buf, "X\n");
3754 } else
3755 r = sprintf(buf, "%lu\n", tr->data[info->cpu]->entries >> 10);
3756
3757 mutex_unlock(&trace_types_lock);
3758
3759 ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
3760 return ret;
3761}
3762
3763static ssize_t
3764tracing_entries_write(struct file *filp, const char __user *ubuf,
3765 size_t cnt, loff_t *ppos)
3766{
3767 struct ftrace_entries_info *info = filp->private_data;
3768 unsigned long val;
3769 int ret;
3770
3771 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
3772 if (ret)
3773 return ret;
3774
3775 /* must have at least 1 entry */
3776 if (!val)
3777 return -EINVAL;
3778
3779 /* value is in KB */
3780 val <<= 10;
3781
3782 ret = tracing_resize_ring_buffer(val, info->cpu);
3783 if (ret < 0)
3784 return ret;
3785
3786 *ppos += cnt;
3787
3788 return cnt;
3789}
3790
3791static int
3792tracing_entries_release(struct inode *inode, struct file *filp)
3793{
3794 struct ftrace_entries_info *info = filp->private_data;
3795
3796 kfree(info);
3797
3798 return 0;
3799}
3800
3801static ssize_t
3802tracing_total_entries_read(struct file *filp, char __user *ubuf,
3803 size_t cnt, loff_t *ppos)
3804{
3805 struct trace_array *tr = filp->private_data;
3806 char buf[64];
3807 int r, cpu;
3808 unsigned long size = 0, expanded_size = 0;
3809
3810 mutex_lock(&trace_types_lock);
3811 for_each_tracing_cpu(cpu) {
3812 size += tr->data[cpu]->entries >> 10;
3813 if (!ring_buffer_expanded)
3814 expanded_size += trace_buf_size >> 10;
3815 }
3816 if (ring_buffer_expanded)
3817 r = sprintf(buf, "%lu\n", size);
3818 else
3819 r = sprintf(buf, "%lu (expanded: %lu)\n", size, expanded_size);
3820 mutex_unlock(&trace_types_lock);
3821
3822 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
3823}
3824
3825static ssize_t
3826tracing_free_buffer_write(struct file *filp, const char __user *ubuf,
3827 size_t cnt, loff_t *ppos)
3828{
3829 /*
3830 * There is no need to read what the user has written, this function
3831 * is just to make sure that there is no error when "echo" is used
3832 */
3833
3834 *ppos += cnt;
3835
3836 return cnt;
3837}
3838
3839static int
3840tracing_free_buffer_release(struct inode *inode, struct file *filp)
3841{
3842 /* disable tracing ? */
3843 if (trace_flags & TRACE_ITER_STOP_ON_FREE)
3844 tracing_off();
3845 /* resize the ring buffer to 0 */
3846 tracing_resize_ring_buffer(0, RING_BUFFER_ALL_CPUS);
3847
3848 return 0;
3849}
3850
3851static ssize_t
3852tracing_mark_write(struct file *filp, const char __user *ubuf,
3853 size_t cnt, loff_t *fpos)
3854{
3855 unsigned long addr = (unsigned long)ubuf;
3856 struct ring_buffer_event *event;
3857 struct ring_buffer *buffer;
3858 struct print_entry *entry;
3859 unsigned long irq_flags;
3860 struct page *pages[2];
3861 void *map_page[2];
3862 int nr_pages = 1;
3863 ssize_t written;
3864 int offset;
3865 int size;
3866 int len;
3867 int ret;
3868 int i;
3869
3870 if (tracing_disabled)
3871 return -EINVAL;
3872
3873 if (cnt > TRACE_BUF_SIZE)
3874 cnt = TRACE_BUF_SIZE;
3875
3876 /*
3877 * Userspace is injecting traces into the kernel trace buffer.
3878 * We want to be as non intrusive as possible.
3879 * To do so, we do not want to allocate any special buffers
3880 * or take any locks, but instead write the userspace data
3881 * straight into the ring buffer.
3882 *
3883 * First we need to pin the userspace buffer into memory,
3884 * which, most likely it is, because it just referenced it.
3885 * But there's no guarantee that it is. By using get_user_pages_fast()
3886 * and kmap_atomic/kunmap_atomic() we can get access to the
3887 * pages directly. We then write the data directly into the
3888 * ring buffer.
3889 */
3890 BUILD_BUG_ON(TRACE_BUF_SIZE >= PAGE_SIZE);
3891
3892 /* check if we cross pages */
3893 if ((addr & PAGE_MASK) != ((addr + cnt) & PAGE_MASK))
3894 nr_pages = 2;
3895
3896 offset = addr & (PAGE_SIZE - 1);
3897 addr &= PAGE_MASK;
3898
3899 ret = get_user_pages_fast(addr, nr_pages, 0, pages);
3900 if (ret < nr_pages) {
3901 while (--ret >= 0)
3902 put_page(pages[ret]);
3903 written = -EFAULT;
3904 goto out;
3905 }
3906
3907 for (i = 0; i < nr_pages; i++)
3908 map_page[i] = kmap_atomic(pages[i]);
3909
3910 local_save_flags(irq_flags);
3911 size = sizeof(*entry) + cnt + 2; /* possible \n added */
3912 buffer = global_trace.buffer;
3913 event = trace_buffer_lock_reserve(buffer, TRACE_PRINT, size,
3914 irq_flags, preempt_count());
3915 if (!event) {
3916 /* Ring buffer disabled, return as if not open for write */
3917 written = -EBADF;
3918 goto out_unlock;
3919 }
3920
3921 entry = ring_buffer_event_data(event);
3922 entry->ip = _THIS_IP_;
3923
3924 if (nr_pages == 2) {
3925 len = PAGE_SIZE - offset;
3926 memcpy(&entry->buf, map_page[0] + offset, len);
3927 memcpy(&entry->buf[len], map_page[1], cnt - len);
3928 } else
3929 memcpy(&entry->buf, map_page[0] + offset, cnt);
3930
3931 if (entry->buf[cnt - 1] != '\n') {
3932 entry->buf[cnt] = '\n';
3933 entry->buf[cnt + 1] = '\0';
3934 } else
3935 entry->buf[cnt] = '\0';
3936
3937 ring_buffer_unlock_commit(buffer, event);
3938
3939 written = cnt;
3940
3941 *fpos += written;
3942
3943 out_unlock:
3944 for (i = 0; i < nr_pages; i++){
3945 kunmap_atomic(map_page[i]);
3946 put_page(pages[i]);
3947 }
3948 out:
3949 return written;
3950}
3951
3952static int tracing_clock_show(struct seq_file *m, void *v)
3953{
3954 int i;
3955
3956 for (i = 0; i < ARRAY_SIZE(trace_clocks); i++)
3957 seq_printf(m,
3958 "%s%s%s%s", i ? " " : "",
3959 i == trace_clock_id ? "[" : "", trace_clocks[i].name,
3960 i == trace_clock_id ? "]" : "");
3961 seq_putc(m, '\n');
3962
3963 return 0;
3964}
3965
3966static ssize_t tracing_clock_write(struct file *filp, const char __user *ubuf,
3967 size_t cnt, loff_t *fpos)
3968{
3969 char buf[64];
3970 const char *clockstr;
3971 int i;
3972
3973 if (cnt >= sizeof(buf))
3974 return -EINVAL;
3975
3976 if (copy_from_user(&buf, ubuf, cnt))
3977 return -EFAULT;
3978
3979 buf[cnt] = 0;
3980
3981 clockstr = strstrip(buf);
3982
3983 for (i = 0; i < ARRAY_SIZE(trace_clocks); i++) {
3984 if (strcmp(trace_clocks[i].name, clockstr) == 0)
3985 break;
3986 }
3987 if (i == ARRAY_SIZE(trace_clocks))
3988 return -EINVAL;
3989
3990 trace_clock_id = i;
3991
3992 mutex_lock(&trace_types_lock);
3993
3994 ring_buffer_set_clock(global_trace.buffer, trace_clocks[i].func);
3995 if (max_tr.buffer)
3996 ring_buffer_set_clock(max_tr.buffer, trace_clocks[i].func);
3997
3998 mutex_unlock(&trace_types_lock);
3999
4000 *fpos += cnt;
4001
4002 return cnt;
4003}
4004
4005static int tracing_clock_open(struct inode *inode, struct file *file)
4006{
4007 if (tracing_disabled)
4008 return -ENODEV;
4009 return single_open(file, tracing_clock_show, NULL);
4010}
4011
4012static const struct file_operations tracing_max_lat_fops = {
4013 .open = tracing_open_generic,
4014 .read = tracing_max_lat_read,
4015 .write = tracing_max_lat_write,
4016 .llseek = generic_file_llseek,
4017};
4018
4019static const struct file_operations tracing_ctrl_fops = {
4020 .open = tracing_open_generic,
4021 .read = tracing_ctrl_read,
4022 .write = tracing_ctrl_write,
4023 .llseek = generic_file_llseek,
4024};
4025
4026static const struct file_operations set_tracer_fops = {
4027 .open = tracing_open_generic,
4028 .read = tracing_set_trace_read,
4029 .write = tracing_set_trace_write,
4030 .llseek = generic_file_llseek,
4031};
4032
4033static const struct file_operations tracing_pipe_fops = {
4034 .open = tracing_open_pipe,
4035 .poll = tracing_poll_pipe,
4036 .read = tracing_read_pipe,
4037 .splice_read = tracing_splice_read_pipe,
4038 .release = tracing_release_pipe,
4039 .llseek = no_llseek,
4040};
4041
4042static const struct file_operations tracing_entries_fops = {
4043 .open = tracing_entries_open,
4044 .read = tracing_entries_read,
4045 .write = tracing_entries_write,
4046 .release = tracing_entries_release,
4047 .llseek = generic_file_llseek,
4048};
4049
4050static const struct file_operations tracing_total_entries_fops = {
4051 .open = tracing_open_generic,
4052 .read = tracing_total_entries_read,
4053 .llseek = generic_file_llseek,
4054};
4055
4056static const struct file_operations tracing_free_buffer_fops = {
4057 .write = tracing_free_buffer_write,
4058 .release = tracing_free_buffer_release,
4059};
4060
4061static const struct file_operations tracing_mark_fops = {
4062 .open = tracing_open_generic,
4063 .write = tracing_mark_write,
4064 .llseek = generic_file_llseek,
4065};
4066
4067static const struct file_operations trace_clock_fops = {
4068 .open = tracing_clock_open,
4069 .read = seq_read,
4070 .llseek = seq_lseek,
4071 .release = single_release,
4072 .write = tracing_clock_write,
4073};
4074
4075struct ftrace_buffer_info {
4076 struct trace_array *tr;
4077 void *spare;
4078 int cpu;
4079 unsigned int read;
4080};
4081
4082static int tracing_buffers_open(struct inode *inode, struct file *filp)
4083{
4084 int cpu = (int)(long)inode->i_private;
4085 struct ftrace_buffer_info *info;
4086
4087 if (tracing_disabled)
4088 return -ENODEV;
4089
4090 info = kzalloc(sizeof(*info), GFP_KERNEL);
4091 if (!info)
4092 return -ENOMEM;
4093
4094 info->tr = &global_trace;
4095 info->cpu = cpu;
4096 info->spare = NULL;
4097 /* Force reading ring buffer for first read */
4098 info->read = (unsigned int)-1;
4099
4100 filp->private_data = info;
4101
4102 return nonseekable_open(inode, filp);
4103}
4104
4105static ssize_t
4106tracing_buffers_read(struct file *filp, char __user *ubuf,
4107 size_t count, loff_t *ppos)
4108{
4109 struct ftrace_buffer_info *info = filp->private_data;
4110 ssize_t ret;
4111 size_t size;
4112
4113 if (!count)
4114 return 0;
4115
4116 if (!info->spare)
4117 info->spare = ring_buffer_alloc_read_page(info->tr->buffer, info->cpu);
4118 if (!info->spare)
4119 return -ENOMEM;
4120
4121 /* Do we have previous read data to read? */
4122 if (info->read < PAGE_SIZE)
4123 goto read;
4124
4125 trace_access_lock(info->cpu);
4126 ret = ring_buffer_read_page(info->tr->buffer,
4127 &info->spare,
4128 count,
4129 info->cpu, 0);
4130 trace_access_unlock(info->cpu);
4131 if (ret < 0)
4132 return 0;
4133
4134 info->read = 0;
4135
4136read:
4137 size = PAGE_SIZE - info->read;
4138 if (size > count)
4139 size = count;
4140
4141 ret = copy_to_user(ubuf, info->spare + info->read, size);
4142 if (ret == size)
4143 return -EFAULT;
4144 size -= ret;
4145
4146 *ppos += size;
4147 info->read += size;
4148
4149 return size;
4150}
4151
4152static int tracing_buffers_release(struct inode *inode, struct file *file)
4153{
4154 struct ftrace_buffer_info *info = file->private_data;
4155
4156 if (info->spare)
4157 ring_buffer_free_read_page(info->tr->buffer, info->spare);
4158 kfree(info);
4159
4160 return 0;
4161}
4162
4163struct buffer_ref {
4164 struct ring_buffer *buffer;
4165 void *page;
4166 int ref;
4167};
4168
4169static void buffer_pipe_buf_release(struct pipe_inode_info *pipe,
4170 struct pipe_buffer *buf)
4171{
4172 struct buffer_ref *ref = (struct buffer_ref *)buf->private;
4173
4174 if (--ref->ref)
4175 return;
4176
4177 ring_buffer_free_read_page(ref->buffer, ref->page);
4178 kfree(ref);
4179 buf->private = 0;
4180}
4181
4182static int buffer_pipe_buf_steal(struct pipe_inode_info *pipe,
4183 struct pipe_buffer *buf)
4184{
4185 return 1;
4186}
4187
4188static void buffer_pipe_buf_get(struct pipe_inode_info *pipe,
4189 struct pipe_buffer *buf)
4190{
4191 struct buffer_ref *ref = (struct buffer_ref *)buf->private;
4192
4193 ref->ref++;
4194}
4195
4196/* Pipe buffer operations for a buffer. */
4197static const struct pipe_buf_operations buffer_pipe_buf_ops = {
4198 .can_merge = 0,
4199 .map = generic_pipe_buf_map,
4200 .unmap = generic_pipe_buf_unmap,
4201 .confirm = generic_pipe_buf_confirm,
4202 .release = buffer_pipe_buf_release,
4203 .steal = buffer_pipe_buf_steal,
4204 .get = buffer_pipe_buf_get,
4205};
4206
4207/*
4208 * Callback from splice_to_pipe(), if we need to release some pages
4209 * at the end of the spd in case we error'ed out in filling the pipe.
4210 */
4211static void buffer_spd_release(struct splice_pipe_desc *spd, unsigned int i)
4212{
4213 struct buffer_ref *ref =
4214 (struct buffer_ref *)spd->partial[i].private;
4215
4216 if (--ref->ref)
4217 return;
4218
4219 ring_buffer_free_read_page(ref->buffer, ref->page);
4220 kfree(ref);
4221 spd->partial[i].private = 0;
4222}
4223
4224static ssize_t
4225tracing_buffers_splice_read(struct file *file, loff_t *ppos,
4226 struct pipe_inode_info *pipe, size_t len,
4227 unsigned int flags)
4228{
4229 struct ftrace_buffer_info *info = file->private_data;
4230 struct partial_page partial_def[PIPE_DEF_BUFFERS];
4231 struct page *pages_def[PIPE_DEF_BUFFERS];
4232 struct splice_pipe_desc spd = {
4233 .pages = pages_def,
4234 .partial = partial_def,
4235 .nr_pages_max = PIPE_DEF_BUFFERS,
4236 .flags = flags,
4237 .ops = &buffer_pipe_buf_ops,
4238 .spd_release = buffer_spd_release,
4239 };
4240 struct buffer_ref *ref;
4241 int entries, size, i;
4242 size_t ret;
4243
4244 if (splice_grow_spd(pipe, &spd))
4245 return -ENOMEM;
4246
4247 if (*ppos & (PAGE_SIZE - 1)) {
4248 WARN_ONCE(1, "Ftrace: previous read must page-align\n");
4249 ret = -EINVAL;
4250 goto out;
4251 }
4252
4253 if (len & (PAGE_SIZE - 1)) {
4254 WARN_ONCE(1, "Ftrace: splice_read should page-align\n");
4255 if (len < PAGE_SIZE) {
4256 ret = -EINVAL;
4257 goto out;
4258 }
4259 len &= PAGE_MASK;
4260 }
4261
4262 trace_access_lock(info->cpu);
4263 entries = ring_buffer_entries_cpu(info->tr->buffer, info->cpu);
4264
4265 for (i = 0; i < pipe->buffers && len && entries; i++, len -= PAGE_SIZE) {
4266 struct page *page;
4267 int r;
4268
4269 ref = kzalloc(sizeof(*ref), GFP_KERNEL);
4270 if (!ref)
4271 break;
4272
4273 ref->ref = 1;
4274 ref->buffer = info->tr->buffer;
4275 ref->page = ring_buffer_alloc_read_page(ref->buffer, info->cpu);
4276 if (!ref->page) {
4277 kfree(ref);
4278 break;
4279 }
4280
4281 r = ring_buffer_read_page(ref->buffer, &ref->page,
4282 len, info->cpu, 1);
4283 if (r < 0) {
4284 ring_buffer_free_read_page(ref->buffer, ref->page);
4285 kfree(ref);
4286 break;
4287 }
4288
4289 /*
4290 * zero out any left over data, this is going to
4291 * user land.
4292 */
4293 size = ring_buffer_page_len(ref->page);
4294 if (size < PAGE_SIZE)
4295 memset(ref->page + size, 0, PAGE_SIZE - size);
4296
4297 page = virt_to_page(ref->page);
4298
4299 spd.pages[i] = page;
4300 spd.partial[i].len = PAGE_SIZE;
4301 spd.partial[i].offset = 0;
4302 spd.partial[i].private = (unsigned long)ref;
4303 spd.nr_pages++;
4304 *ppos += PAGE_SIZE;
4305
4306 entries = ring_buffer_entries_cpu(info->tr->buffer, info->cpu);
4307 }
4308
4309 trace_access_unlock(info->cpu);
4310 spd.nr_pages = i;
4311
4312 /* did we read anything? */
4313 if (!spd.nr_pages) {
4314 if (flags & SPLICE_F_NONBLOCK)
4315 ret = -EAGAIN;
4316 else
4317 ret = 0;
4318 /* TODO: block */
4319 goto out;
4320 }
4321
4322 ret = splice_to_pipe(pipe, &spd);
4323 splice_shrink_spd(&spd);
4324out:
4325 return ret;
4326}
4327
4328static const struct file_operations tracing_buffers_fops = {
4329 .open = tracing_buffers_open,
4330 .read = tracing_buffers_read,
4331 .release = tracing_buffers_release,
4332 .splice_read = tracing_buffers_splice_read,
4333 .llseek = no_llseek,
4334};
4335
4336static ssize_t
4337tracing_stats_read(struct file *filp, char __user *ubuf,
4338 size_t count, loff_t *ppos)
4339{
4340 unsigned long cpu = (unsigned long)filp->private_data;
4341 struct trace_array *tr = &global_trace;
4342 struct trace_seq *s;
4343 unsigned long cnt;
4344 unsigned long long t;
4345 unsigned long usec_rem;
4346
4347 s = kmalloc(sizeof(*s), GFP_KERNEL);
4348 if (!s)
4349 return -ENOMEM;
4350
4351 trace_seq_init(s);
4352
4353 cnt = ring_buffer_entries_cpu(tr->buffer, cpu);
4354 trace_seq_printf(s, "entries: %ld\n", cnt);
4355
4356 cnt = ring_buffer_overrun_cpu(tr->buffer, cpu);
4357 trace_seq_printf(s, "overrun: %ld\n", cnt);
4358
4359 cnt = ring_buffer_commit_overrun_cpu(tr->buffer, cpu);
4360 trace_seq_printf(s, "commit overrun: %ld\n", cnt);
4361
4362 cnt = ring_buffer_bytes_cpu(tr->buffer, cpu);
4363 trace_seq_printf(s, "bytes: %ld\n", cnt);
4364
4365 t = ns2usecs(ring_buffer_oldest_event_ts(tr->buffer, cpu));
4366 usec_rem = do_div(t, USEC_PER_SEC);
4367 trace_seq_printf(s, "oldest event ts: %5llu.%06lu\n", t, usec_rem);
4368
4369 t = ns2usecs(ring_buffer_time_stamp(tr->buffer, cpu));
4370 usec_rem = do_div(t, USEC_PER_SEC);
4371 trace_seq_printf(s, "now ts: %5llu.%06lu\n", t, usec_rem);
4372
4373 count = simple_read_from_buffer(ubuf, count, ppos, s->buffer, s->len);
4374
4375 kfree(s);
4376
4377 return count;
4378}
4379
4380static const struct file_operations tracing_stats_fops = {
4381 .open = tracing_open_generic,
4382 .read = tracing_stats_read,
4383 .llseek = generic_file_llseek,
4384};
4385
4386#ifdef CONFIG_DYNAMIC_FTRACE
4387
4388int __weak ftrace_arch_read_dyn_info(char *buf, int size)
4389{
4390 return 0;
4391}
4392
4393static ssize_t
4394tracing_read_dyn_info(struct file *filp, char __user *ubuf,
4395 size_t cnt, loff_t *ppos)
4396{
4397 static char ftrace_dyn_info_buffer[1024];
4398 static DEFINE_MUTEX(dyn_info_mutex);
4399 unsigned long *p = filp->private_data;
4400 char *buf = ftrace_dyn_info_buffer;
4401 int size = ARRAY_SIZE(ftrace_dyn_info_buffer);
4402 int r;
4403
4404 mutex_lock(&dyn_info_mutex);
4405 r = sprintf(buf, "%ld ", *p);
4406
4407 r += ftrace_arch_read_dyn_info(buf+r, (size-1)-r);
4408 buf[r++] = '\n';
4409
4410 r = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
4411
4412 mutex_unlock(&dyn_info_mutex);
4413
4414 return r;
4415}
4416
4417static const struct file_operations tracing_dyn_info_fops = {
4418 .open = tracing_open_generic,
4419 .read = tracing_read_dyn_info,
4420 .llseek = generic_file_llseek,
4421};
4422#endif
4423
4424static struct dentry *d_tracer;
4425
4426struct dentry *tracing_init_dentry(void)
4427{
4428 static int once;
4429
4430 if (d_tracer)
4431 return d_tracer;
4432
4433 if (!debugfs_initialized())
4434 return NULL;
4435
4436 d_tracer = debugfs_create_dir("tracing", NULL);
4437
4438 if (!d_tracer && !once) {
4439 once = 1;
4440 pr_warning("Could not create debugfs directory 'tracing'\n");
4441 return NULL;
4442 }
4443
4444 return d_tracer;
4445}
4446
4447static struct dentry *d_percpu;
4448
4449struct dentry *tracing_dentry_percpu(void)
4450{
4451 static int once;
4452 struct dentry *d_tracer;
4453
4454 if (d_percpu)
4455 return d_percpu;
4456
4457 d_tracer = tracing_init_dentry();
4458
4459 if (!d_tracer)
4460 return NULL;
4461
4462 d_percpu = debugfs_create_dir("per_cpu", d_tracer);
4463
4464 if (!d_percpu && !once) {
4465 once = 1;
4466 pr_warning("Could not create debugfs directory 'per_cpu'\n");
4467 return NULL;
4468 }
4469
4470 return d_percpu;
4471}
4472
4473static void tracing_init_debugfs_percpu(long cpu)
4474{
4475 struct dentry *d_percpu = tracing_dentry_percpu();
4476 struct dentry *d_cpu;
4477 char cpu_dir[30]; /* 30 characters should be more than enough */
4478
4479 if (!d_percpu)
4480 return;
4481
4482 snprintf(cpu_dir, 30, "cpu%ld", cpu);
4483 d_cpu = debugfs_create_dir(cpu_dir, d_percpu);
4484 if (!d_cpu) {
4485 pr_warning("Could not create debugfs '%s' entry\n", cpu_dir);
4486 return;
4487 }
4488
4489 /* per cpu trace_pipe */
4490 trace_create_file("trace_pipe", 0444, d_cpu,
4491 (void *) cpu, &tracing_pipe_fops);
4492
4493 /* per cpu trace */
4494 trace_create_file("trace", 0644, d_cpu,
4495 (void *) cpu, &tracing_fops);
4496
4497 trace_create_file("trace_pipe_raw", 0444, d_cpu,
4498 (void *) cpu, &tracing_buffers_fops);
4499
4500 trace_create_file("stats", 0444, d_cpu,
4501 (void *) cpu, &tracing_stats_fops);
4502
4503 trace_create_file("buffer_size_kb", 0444, d_cpu,
4504 (void *) cpu, &tracing_entries_fops);
4505}
4506
4507#ifdef CONFIG_FTRACE_SELFTEST
4508/* Let selftest have access to static functions in this file */
4509#include "trace_selftest.c"
4510#endif
4511
4512struct trace_option_dentry {
4513 struct tracer_opt *opt;
4514 struct tracer_flags *flags;
4515 struct dentry *entry;
4516};
4517
4518static ssize_t
4519trace_options_read(struct file *filp, char __user *ubuf, size_t cnt,
4520 loff_t *ppos)
4521{
4522 struct trace_option_dentry *topt = filp->private_data;
4523 char *buf;
4524
4525 if (topt->flags->val & topt->opt->bit)
4526 buf = "1\n";
4527 else
4528 buf = "0\n";
4529
4530 return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
4531}
4532
4533static ssize_t
4534trace_options_write(struct file *filp, const char __user *ubuf, size_t cnt,
4535 loff_t *ppos)
4536{
4537 struct trace_option_dentry *topt = filp->private_data;
4538 unsigned long val;
4539 int ret;
4540
4541 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
4542 if (ret)
4543 return ret;
4544
4545 if (val != 0 && val != 1)
4546 return -EINVAL;
4547
4548 if (!!(topt->flags->val & topt->opt->bit) != val) {
4549 mutex_lock(&trace_types_lock);
4550 ret = __set_tracer_option(current_trace, topt->flags,
4551 topt->opt, !val);
4552 mutex_unlock(&trace_types_lock);
4553 if (ret)
4554 return ret;
4555 }
4556
4557 *ppos += cnt;
4558
4559 return cnt;
4560}
4561
4562
4563static const struct file_operations trace_options_fops = {
4564 .open = tracing_open_generic,
4565 .read = trace_options_read,
4566 .write = trace_options_write,
4567 .llseek = generic_file_llseek,
4568};
4569
4570static ssize_t
4571trace_options_core_read(struct file *filp, char __user *ubuf, size_t cnt,
4572 loff_t *ppos)
4573{
4574 long index = (long)filp->private_data;
4575 char *buf;
4576
4577 if (trace_flags & (1 << index))
4578 buf = "1\n";
4579 else
4580 buf = "0\n";
4581
4582 return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
4583}
4584
4585static ssize_t
4586trace_options_core_write(struct file *filp, const char __user *ubuf, size_t cnt,
4587 loff_t *ppos)
4588{
4589 long index = (long)filp->private_data;
4590 unsigned long val;
4591 int ret;
4592
4593 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
4594 if (ret)
4595 return ret;
4596
4597 if (val != 0 && val != 1)
4598 return -EINVAL;
4599 set_tracer_flags(1 << index, val);
4600
4601 *ppos += cnt;
4602
4603 return cnt;
4604}
4605
4606static const struct file_operations trace_options_core_fops = {
4607 .open = tracing_open_generic,
4608 .read = trace_options_core_read,
4609 .write = trace_options_core_write,
4610 .llseek = generic_file_llseek,
4611};
4612
4613struct dentry *trace_create_file(const char *name,
4614 umode_t mode,
4615 struct dentry *parent,
4616 void *data,
4617 const struct file_operations *fops)
4618{
4619 struct dentry *ret;
4620
4621 ret = debugfs_create_file(name, mode, parent, data, fops);
4622 if (!ret)
4623 pr_warning("Could not create debugfs '%s' entry\n", name);
4624
4625 return ret;
4626}
4627
4628
4629static struct dentry *trace_options_init_dentry(void)
4630{
4631 struct dentry *d_tracer;
4632 static struct dentry *t_options;
4633
4634 if (t_options)
4635 return t_options;
4636
4637 d_tracer = tracing_init_dentry();
4638 if (!d_tracer)
4639 return NULL;
4640
4641 t_options = debugfs_create_dir("options", d_tracer);
4642 if (!t_options) {
4643 pr_warning("Could not create debugfs directory 'options'\n");
4644 return NULL;
4645 }
4646
4647 return t_options;
4648}
4649
4650static void
4651create_trace_option_file(struct trace_option_dentry *topt,
4652 struct tracer_flags *flags,
4653 struct tracer_opt *opt)
4654{
4655 struct dentry *t_options;
4656
4657 t_options = trace_options_init_dentry();
4658 if (!t_options)
4659 return;
4660
4661 topt->flags = flags;
4662 topt->opt = opt;
4663
4664 topt->entry = trace_create_file(opt->name, 0644, t_options, topt,
4665 &trace_options_fops);
4666
4667}
4668
4669static struct trace_option_dentry *
4670create_trace_option_files(struct tracer *tracer)
4671{
4672 struct trace_option_dentry *topts;
4673 struct tracer_flags *flags;
4674 struct tracer_opt *opts;
4675 int cnt;
4676
4677 if (!tracer)
4678 return NULL;
4679
4680 flags = tracer->flags;
4681
4682 if (!flags || !flags->opts)
4683 return NULL;
4684
4685 opts = flags->opts;
4686
4687 for (cnt = 0; opts[cnt].name; cnt++)
4688 ;
4689
4690 topts = kcalloc(cnt + 1, sizeof(*topts), GFP_KERNEL);
4691 if (!topts)
4692 return NULL;
4693
4694 for (cnt = 0; opts[cnt].name; cnt++)
4695 create_trace_option_file(&topts[cnt], flags,
4696 &opts[cnt]);
4697
4698 return topts;
4699}
4700
4701static void
4702destroy_trace_option_files(struct trace_option_dentry *topts)
4703{
4704 int cnt;
4705
4706 if (!topts)
4707 return;
4708
4709 for (cnt = 0; topts[cnt].opt; cnt++) {
4710 if (topts[cnt].entry)
4711 debugfs_remove(topts[cnt].entry);
4712 }
4713
4714 kfree(topts);
4715}
4716
4717static struct dentry *
4718create_trace_option_core_file(const char *option, long index)
4719{
4720 struct dentry *t_options;
4721
4722 t_options = trace_options_init_dentry();
4723 if (!t_options)
4724 return NULL;
4725
4726 return trace_create_file(option, 0644, t_options, (void *)index,
4727 &trace_options_core_fops);
4728}
4729
4730static __init void create_trace_options_dir(void)
4731{
4732 struct dentry *t_options;
4733 int i;
4734
4735 t_options = trace_options_init_dentry();
4736 if (!t_options)
4737 return;
4738
4739 for (i = 0; trace_options[i]; i++)
4740 create_trace_option_core_file(trace_options[i], i);
4741}
4742
4743static ssize_t
4744rb_simple_read(struct file *filp, char __user *ubuf,
4745 size_t cnt, loff_t *ppos)
4746{
4747 struct trace_array *tr = filp->private_data;
4748 struct ring_buffer *buffer = tr->buffer;
4749 char buf[64];
4750 int r;
4751
4752 if (buffer)
4753 r = ring_buffer_record_is_on(buffer);
4754 else
4755 r = 0;
4756
4757 r = sprintf(buf, "%d\n", r);
4758
4759 return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
4760}
4761
4762static ssize_t
4763rb_simple_write(struct file *filp, const char __user *ubuf,
4764 size_t cnt, loff_t *ppos)
4765{
4766 struct trace_array *tr = filp->private_data;
4767 struct ring_buffer *buffer = tr->buffer;
4768 unsigned long val;
4769 int ret;
4770
4771 ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
4772 if (ret)
4773 return ret;
4774
4775 if (buffer) {
4776 if (val)
4777 ring_buffer_record_on(buffer);
4778 else
4779 ring_buffer_record_off(buffer);
4780 }
4781
4782 (*ppos)++;
4783
4784 return cnt;
4785}
4786
4787static const struct file_operations rb_simple_fops = {
4788 .open = tracing_open_generic,
4789 .read = rb_simple_read,
4790 .write = rb_simple_write,
4791 .llseek = default_llseek,
4792};
4793
4794static __init int tracer_init_debugfs(void)
4795{
4796 struct dentry *d_tracer;
4797 int cpu;
4798
4799 trace_access_lock_init();
4800
4801 d_tracer = tracing_init_dentry();
4802
4803 trace_create_file("tracing_enabled", 0644, d_tracer,
4804 &global_trace, &tracing_ctrl_fops);
4805
4806 trace_create_file("trace_options", 0644, d_tracer,
4807 NULL, &tracing_iter_fops);
4808
4809 trace_create_file("tracing_cpumask", 0644, d_tracer,
4810 NULL, &tracing_cpumask_fops);
4811
4812 trace_create_file("trace", 0644, d_tracer,
4813 (void *) TRACE_PIPE_ALL_CPU, &tracing_fops);
4814
4815 trace_create_file("available_tracers", 0444, d_tracer,
4816 &global_trace, &show_traces_fops);
4817
4818 trace_create_file("current_tracer", 0644, d_tracer,
4819 &global_trace, &set_tracer_fops);
4820
4821#ifdef CONFIG_TRACER_MAX_TRACE
4822 trace_create_file("tracing_max_latency", 0644, d_tracer,
4823 &tracing_max_latency, &tracing_max_lat_fops);
4824#endif
4825
4826 trace_create_file("tracing_thresh", 0644, d_tracer,
4827 &tracing_thresh, &tracing_max_lat_fops);
4828
4829 trace_create_file("README", 0444, d_tracer,
4830 NULL, &tracing_readme_fops);
4831
4832 trace_create_file("trace_pipe", 0444, d_tracer,
4833 (void *) TRACE_PIPE_ALL_CPU, &tracing_pipe_fops);
4834
4835 trace_create_file("buffer_size_kb", 0644, d_tracer,
4836 (void *) RING_BUFFER_ALL_CPUS, &tracing_entries_fops);
4837
4838 trace_create_file("buffer_total_size_kb", 0444, d_tracer,
4839 &global_trace, &tracing_total_entries_fops);
4840
4841 trace_create_file("free_buffer", 0644, d_tracer,
4842 &global_trace, &tracing_free_buffer_fops);
4843
4844 trace_create_file("trace_marker", 0220, d_tracer,
4845 NULL, &tracing_mark_fops);
4846
4847 trace_create_file("saved_cmdlines", 0444, d_tracer,
4848 NULL, &tracing_saved_cmdlines_fops);
4849
4850 trace_create_file("trace_clock", 0644, d_tracer, NULL,
4851 &trace_clock_fops);
4852
4853 trace_create_file("tracing_on", 0644, d_tracer,
4854 &global_trace, &rb_simple_fops);
4855
4856#ifdef CONFIG_DYNAMIC_FTRACE
4857 trace_create_file("dyn_ftrace_total_info", 0444, d_tracer,
4858 &ftrace_update_tot_cnt, &tracing_dyn_info_fops);
4859#endif
4860
4861 create_trace_options_dir();
4862
4863 for_each_tracing_cpu(cpu)
4864 tracing_init_debugfs_percpu(cpu);
4865
4866 return 0;
4867}
4868
4869static int trace_panic_handler(struct notifier_block *this,
4870 unsigned long event, void *unused)
4871{
4872 if (ftrace_dump_on_oops)
4873 ftrace_dump(ftrace_dump_on_oops);
4874 return NOTIFY_OK;
4875}
4876
4877static struct notifier_block trace_panic_notifier = {
4878 .notifier_call = trace_panic_handler,
4879 .next = NULL,
4880 .priority = 150 /* priority: INT_MAX >= x >= 0 */
4881};
4882
4883static int trace_die_handler(struct notifier_block *self,
4884 unsigned long val,
4885 void *data)
4886{
4887 switch (val) {
4888 case DIE_OOPS:
4889 if (ftrace_dump_on_oops)
4890 ftrace_dump(ftrace_dump_on_oops);
4891 break;
4892 default:
4893 break;
4894 }
4895 return NOTIFY_OK;
4896}
4897
4898static struct notifier_block trace_die_notifier = {
4899 .notifier_call = trace_die_handler,
4900 .priority = 200
4901};
4902
4903/*
4904 * printk is set to max of 1024, we really don't need it that big.
4905 * Nothing should be printing 1000 characters anyway.
4906 */
4907#define TRACE_MAX_PRINT 1000
4908
4909/*
4910 * Define here KERN_TRACE so that we have one place to modify
4911 * it if we decide to change what log level the ftrace dump
4912 * should be at.
4913 */
4914#define KERN_TRACE KERN_EMERG
4915
4916void
4917trace_printk_seq(struct trace_seq *s)
4918{
4919 /* Probably should print a warning here. */
4920 if (s->len >= 1000)
4921 s->len = 1000;
4922
4923 /* should be zero ended, but we are paranoid. */
4924 s->buffer[s->len] = 0;
4925
4926 printk(KERN_TRACE "%s", s->buffer);
4927
4928 trace_seq_init(s);
4929}
4930
4931void trace_init_global_iter(struct trace_iterator *iter)
4932{
4933 iter->tr = &global_trace;
4934 iter->trace = current_trace;
4935 iter->cpu_file = TRACE_PIPE_ALL_CPU;
4936}
4937
4938static void
4939__ftrace_dump(bool disable_tracing, enum ftrace_dump_mode oops_dump_mode)
4940{
4941 static arch_spinlock_t ftrace_dump_lock =
4942 (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
4943 /* use static because iter can be a bit big for the stack */
4944 static struct trace_iterator iter;
4945 unsigned int old_userobj;
4946 static int dump_ran;
4947 unsigned long flags;
4948 int cnt = 0, cpu;
4949
4950 /* only one dump */
4951 local_irq_save(flags);
4952 arch_spin_lock(&ftrace_dump_lock);
4953 if (dump_ran)
4954 goto out;
4955
4956 dump_ran = 1;
4957
4958 tracing_off();
4959
4960 /* Did function tracer already get disabled? */
4961 if (ftrace_is_dead()) {
4962 printk("# WARNING: FUNCTION TRACING IS CORRUPTED\n");
4963 printk("# MAY BE MISSING FUNCTION EVENTS\n");
4964 }
4965
4966 if (disable_tracing)
4967 ftrace_kill();
4968
4969 trace_init_global_iter(&iter);
4970
4971 for_each_tracing_cpu(cpu) {
4972 atomic_inc(&iter.tr->data[cpu]->disabled);
4973 }
4974
4975 old_userobj = trace_flags & TRACE_ITER_SYM_USEROBJ;
4976
4977 /* don't look at user memory in panic mode */
4978 trace_flags &= ~TRACE_ITER_SYM_USEROBJ;
4979
4980 /* Simulate the iterator */
4981 iter.tr = &global_trace;
4982 iter.trace = current_trace;
4983
4984 switch (oops_dump_mode) {
4985 case DUMP_ALL:
4986 iter.cpu_file = TRACE_PIPE_ALL_CPU;
4987 break;
4988 case DUMP_ORIG:
4989 iter.cpu_file = raw_smp_processor_id();
4990 break;
4991 case DUMP_NONE:
4992 goto out_enable;
4993 default:
4994 printk(KERN_TRACE "Bad dumping mode, switching to all CPUs dump\n");
4995 iter.cpu_file = TRACE_PIPE_ALL_CPU;
4996 }
4997
4998 printk(KERN_TRACE "Dumping ftrace buffer:\n");
4999
5000 /*
5001 * We need to stop all tracing on all CPUS to read the
5002 * the next buffer. This is a bit expensive, but is
5003 * not done often. We fill all what we can read,
5004 * and then release the locks again.
5005 */
5006
5007 while (!trace_empty(&iter)) {
5008
5009 if (!cnt)
5010 printk(KERN_TRACE "---------------------------------\n");
5011
5012 cnt++;
5013
5014 /* reset all but tr, trace, and overruns */
5015 memset(&iter.seq, 0,
5016 sizeof(struct trace_iterator) -
5017 offsetof(struct trace_iterator, seq));
5018 iter.iter_flags |= TRACE_FILE_LAT_FMT;
5019 iter.pos = -1;
5020
5021 if (trace_find_next_entry_inc(&iter) != NULL) {
5022 int ret;
5023
5024 ret = print_trace_line(&iter);
5025 if (ret != TRACE_TYPE_NO_CONSUME)
5026 trace_consume(&iter);
5027 }
5028 touch_nmi_watchdog();
5029
5030 trace_printk_seq(&iter.seq);
5031 }
5032
5033 if (!cnt)
5034 printk(KERN_TRACE " (ftrace buffer empty)\n");
5035 else
5036 printk(KERN_TRACE "---------------------------------\n");
5037
5038 out_enable:
5039 /* Re-enable tracing if requested */
5040 if (!disable_tracing) {
5041 trace_flags |= old_userobj;
5042
5043 for_each_tracing_cpu(cpu) {
5044 atomic_dec(&iter.tr->data[cpu]->disabled);
5045 }
5046 tracing_on();
5047 }
5048
5049 out:
5050 arch_spin_unlock(&ftrace_dump_lock);
5051 local_irq_restore(flags);
5052}
5053
5054/* By default: disable tracing after the dump */
5055void ftrace_dump(enum ftrace_dump_mode oops_dump_mode)
5056{
5057 __ftrace_dump(true, oops_dump_mode);
5058}
5059EXPORT_SYMBOL_GPL(ftrace_dump);
5060
5061__init static int tracer_alloc_buffers(void)
5062{
5063 int ring_buf_size;
5064 enum ring_buffer_flags rb_flags;
5065 int i;
5066 int ret = -ENOMEM;
5067
5068
5069 if (!alloc_cpumask_var(&tracing_buffer_mask, GFP_KERNEL))
5070 goto out;
5071
5072 if (!alloc_cpumask_var(&tracing_cpumask, GFP_KERNEL))
5073 goto out_free_buffer_mask;
5074
5075 /* Only allocate trace_printk buffers if a trace_printk exists */
5076 if (__stop___trace_bprintk_fmt != __start___trace_bprintk_fmt)
5077 trace_printk_init_buffers();
5078
5079 /* To save memory, keep the ring buffer size to its minimum */
5080 if (ring_buffer_expanded)
5081 ring_buf_size = trace_buf_size;
5082 else
5083 ring_buf_size = 1;
5084
5085 rb_flags = trace_flags & TRACE_ITER_OVERWRITE ? RB_FL_OVERWRITE : 0;
5086
5087 cpumask_copy(tracing_buffer_mask, cpu_possible_mask);
5088 cpumask_copy(tracing_cpumask, cpu_all_mask);
5089
5090 /* TODO: make the number of buffers hot pluggable with CPUS */
5091 global_trace.buffer = ring_buffer_alloc(ring_buf_size, rb_flags);
5092 if (!global_trace.buffer) {
5093 printk(KERN_ERR "tracer: failed to allocate ring buffer!\n");
5094 WARN_ON(1);
5095 goto out_free_cpumask;
5096 }
5097 if (global_trace.buffer_disabled)
5098 tracing_off();
5099
5100
5101#ifdef CONFIG_TRACER_MAX_TRACE
5102 max_tr.buffer = ring_buffer_alloc(1, rb_flags);
5103 if (!max_tr.buffer) {
5104 printk(KERN_ERR "tracer: failed to allocate max ring buffer!\n");
5105 WARN_ON(1);
5106 ring_buffer_free(global_trace.buffer);
5107 goto out_free_cpumask;
5108 }
5109#endif
5110
5111 /* Allocate the first page for all buffers */
5112 for_each_tracing_cpu(i) {
5113 global_trace.data[i] = &per_cpu(global_trace_cpu, i);
5114 max_tr.data[i] = &per_cpu(max_tr_data, i);
5115 }
5116
5117 set_buffer_entries(&global_trace,
5118 ring_buffer_size(global_trace.buffer, 0));
5119#ifdef CONFIG_TRACER_MAX_TRACE
5120 set_buffer_entries(&max_tr, 1);
5121#endif
5122
5123 trace_init_cmdlines();
5124
5125 register_tracer(&nop_trace);
5126 current_trace = &nop_trace;
5127 /* All seems OK, enable tracing */
5128 tracing_disabled = 0;
5129
5130 atomic_notifier_chain_register(&panic_notifier_list,
5131 &trace_panic_notifier);
5132
5133 register_die_notifier(&trace_die_notifier);
5134
5135 return 0;
5136
5137out_free_cpumask:
5138 free_cpumask_var(tracing_cpumask);
5139out_free_buffer_mask:
5140 free_cpumask_var(tracing_buffer_mask);
5141out:
5142 return ret;
5143}
5144
5145__init static int clear_boot_tracer(void)
5146{
5147 /*
5148 * The default tracer at boot buffer is an init section.
5149 * This function is called in lateinit. If we did not
5150 * find the boot tracer, then clear it out, to prevent
5151 * later registration from accessing the buffer that is
5152 * about to be freed.
5153 */
5154 if (!default_bootup_tracer)
5155 return 0;
5156
5157 printk(KERN_INFO "ftrace bootup tracer '%s' not registered.\n",
5158 default_bootup_tracer);
5159 default_bootup_tracer = NULL;
5160
5161 return 0;
5162}
5163
5164early_initcall(tracer_alloc_buffers);
5165fs_initcall(tracer_init_debugfs);
5166late_initcall(clear_boot_tracer);